From 5b40508c3b03e38a9016ada3ad5fbebb996fc588 Mon Sep 17 00:00:00 2001
From: Carl Christian Snethlage <cc.snethlage@gmail.com>
Date: Fri, 10 Jan 2020 23:17:17 +0100
Subject: [PATCH 1/9] Converted GroupDialog to mvvm pattern

---
 .../org/jabref/gui/groups/GroupDialog.fxml    | 118 +++++
 .../org/jabref/gui/groups/GroupDialog.java    |   4 +-
 .../jabref/gui/groups/GroupDialogView.java    | 148 ++++++
 .../gui/groups/GroupDialogViewModel.java      | 493 ++++++++++++++++++
 .../jabref/gui/groups/GroupTreeViewModel.java |   4 +-
 src/main/resources/l10n/JabRef_en.properties  |   6 +-
 6 files changed, 768 insertions(+), 5 deletions(-)
 create mode 100644 src/main/java/org/jabref/gui/groups/GroupDialog.fxml
 create mode 100644 src/main/java/org/jabref/gui/groups/GroupDialogView.java
 create mode 100644 src/main/java/org/jabref/gui/groups/GroupDialogViewModel.java

diff --git a/src/main/java/org/jabref/gui/groups/GroupDialog.fxml b/src/main/java/org/jabref/gui/groups/GroupDialog.fxml
new file mode 100644
index 00000000000..e1a106660d1
--- /dev/null
+++ b/src/main/java/org/jabref/gui/groups/GroupDialog.fxml
@@ -0,0 +1,118 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.scene.control.*?>
+<?import javafx.scene.layout.*?>
+
+<?import javafx.geometry.Insets?>
+<?import javafx.scene.text.TextFlow?>
+<DialogPane prefHeight="300.0" prefWidth="700.0" xmlns="http://javafx.com/javafx/10.0.2-internal"
+            xmlns:fx="http://javafx.com/fxml/1" fx:controller="org.jabref.gui.groups.GroupDialogView">
+    <content>
+        <fx:define>
+            <ToggleGroup fx:id="hierarchicalContext"/>
+            <ToggleGroup fx:id="type"/>
+            <ToggleGroup fx:id="autoGroupOptions"/>
+        </fx:define>
+        <VBox>
+            <SplitPane dividerPositions="0.5">
+                <VBox spacing="10.0" minWidth="150">
+                    <padding>
+                        <Insets bottom="4.0" left="4.0" right="4.0" top="4.0"/>
+                    </padding>
+                    <Label styleClass="sectionHeader" text="%General"/>
+                    <Label text="%Name"/>
+                    <TextField fx:id="nameField"/>
+                    <Label text="%Description"/>
+                    <TextField fx:id="descriptionField"/>
+                    <HBox spacing="10.0">
+                        <VBox HBox.hgrow="ALWAYS">
+                            <Label text="%Icon"/>
+                            <TextField fx:id="iconField"/>
+                        </VBox>
+                        <VBox layoutX="10.0" layoutY="10.0" HBox.hgrow="ALWAYS">
+                            <Label text="%Color"/>
+                            <ColorPicker fx:id="colorField"/>
+                        </VBox>
+                    </HBox>
+                    <Label text="%Hierarchical context"/>
+                    <RadioButton fx:id="independentButton" toggleGroup="$hierarchicalContext" wrapText="true"
+                                 text="%Independent group: When selected, view only this group's entries"/>
+                    <RadioButton fx:id="intersectionButton" toggleGroup="$hierarchicalContext" wrapText="true"
+                                 text="%Refine supergroup: When selected, view entries contained in both this group and its supergroup"/>
+                    <RadioButton fx:id="unionButton" toggleGroup="$hierarchicalContext" wrapText="true"
+                                 text="%Include subgroups: When selected, view entries contained in this group or its subgroups"/>
+                    <Label text="%Type"/>
+                    <RadioButton fx:id="explicitRadioButton" toggleGroup="$type" wrapText="true"
+                                 text="%Statically group entries by manual assignment"/>
+                    <RadioButton fx:id="keywordsRadioButton" toggleGroup="$type" wrapText="true"
+                                 text="%Dynamically group entries by searching a field for a keyword"/>
+                    <RadioButton fx:id="searchRadioButton" toggleGroup="$type" wrapText="true"
+                                 text="%Dynamically group entries by a free-form search expression"/>
+                    <RadioButton fx:id="autoRadioButton" toggleGroup="$type" wrapText="true"
+                                 text="%Automatically create groups"/>
+                    <RadioButton fx:id="texRadioButton" toggleGroup="$type" wrapText="true"
+                                 text="%Group containing entries cited in a given TeX file"/>
+                </VBox>
+                <VBox minWidth="150">
+                    <padding>
+                        <Insets bottom="4.0" left="4.0" right="4.0" top="4.0"/>
+                    </padding>
+                    <Label styleClass="sectionHeader" text="%Options"/>
+                    <StackPane>
+                        <VBox visible="${keywordsRadioButton.selected}" spacing="10.0">
+                            <Label text="%Field"/>
+                            <TextField fx:id="keyWordGroupSearchTerm"/>
+                            <Label text="%Keyword"/>
+                            <TextField fx:id="keyWordGroupSearchField"/>
+                            <CheckBox fx:id="keywordGroupCaseSensitive" text="Case sensitive"/>
+                            <CheckBox fx:id="keywordGroupRegExp" text="Regular expression"/>
+                        </VBox>
+                        <VBox visible="${searchRadioButton.selected}" spacing="10.0">
+                            <Label text="%Search expression"/>
+                            <TextField fx:id="searchGroupSearchExpression"/>
+                            <CheckBox fx:id="searchGroupCaseSensitive" text="Case sensitive"/>
+                            <CheckBox fx:id="searchGroupRegExp" text="Regular expression"/>
+                        </VBox>
+                        <VBox visible="${autoRadioButton.selected}" spacing="10.0">
+                            <RadioButton fx:id="autoGroupKeywordsOption" toggleGroup="$autoGroupOptions"
+                                         text="Generate groups from keywords in a BibTeX field"/>
+                            <VBox spacing="10.0">
+                                <padding>
+                                    <Insets left="20.0"/>
+                                </padding>
+                                <Label text="%Field to group by:"/>
+                                <TextField fx:id="autoGroupKeywordsField"
+                                           disable="${!autoGroupKeywordsOption.selected}"/>
+                                <Label text="%Use the following delimiter character(s):"/>
+                                <HBox spacing="10.0">
+                                    <TextField fx:id="autoGroupKeywordsDeliminator"
+                                               disable="${!autoGroupKeywordsOption.selected}"/>
+                                    <TextField fx:id="autoGroupKeywordsHierarchicalDeliminator"
+                                               disable="${!autoGroupKeywordsOption.selected}"/>
+                                </HBox>
+                            </VBox>
+                            <RadioButton fx:id="autoGroupPersonsOption" toggleGroup="$autoGroupOptions"
+                                         text="Generate groups from keywords in a BibTeX field"/>
+                            <Label text="%Field to group by:"/>
+                            <TextField fx:id="autoGroupPersonsField" disable="${!autoGroupPersonsOption.selected}"/>
+                        </VBox>
+                        <VBox visible="${texRadioButton.selected}" spacing="10.0">
+                            <Label text="%Aux file"/>
+                            <VBox spacing="10.0">
+                                <padding>
+                                    <Insets left="20.0"/>
+                                </padding>
+                                <HBox spacing="10.0">
+                                    <TextField fx:id="texGroupFilePath" HBox.hgrow="ALWAYS"/>
+                                    <Button onAction="#texGroupBrowse" text="%Browse"/>
+                                </HBox>
+                            </VBox>
+                        </VBox>
+                    </StackPane>
+                </VBox>
+            </SplitPane>
+            <TextFlow fx:id="hintTextFlow" VBox.vgrow="ALWAYS"
+                      minHeight="120" minWidth="400"/>
+        </VBox>
+    </content>
+</DialogPane>
diff --git a/src/main/java/org/jabref/gui/groups/GroupDialog.java b/src/main/java/org/jabref/gui/groups/GroupDialog.java
index c97550dce12..9097cc244b9 100644
--- a/src/main/java/org/jabref/gui/groups/GroupDialog.java
+++ b/src/main/java/org/jabref/gui/groups/GroupDialog.java
@@ -480,7 +480,7 @@ private VBox createOptionsAutoGroup() {
         autoGroupKeywordsOption.setToggleGroup(tg);
         autoGroupPersonsOption.setToggleGroup(tg);
         VBox fieldToGroupByKeywords = new VBox(
-                new Label(Localization.lang("Field to group by") + ":"),
+                new Label(Localization.lang("Field to group by:")),
                 autoGroupKeywordsField
         );
         fieldToGroupByKeywords.setPadding(new Insets(0, 0, 0, 20));
@@ -493,7 +493,7 @@ private VBox createOptionsAutoGroup() {
         );
         delimiterCharacters.setPadding(new Insets(0, 0, 0, 20));
         VBox fieldToGroupByPersons = new VBox(
-                new Label(Localization.lang("Field to group by") + ":"),
+                new Label(Localization.lang("Field to group by:")),
                 autoGroupPersonsField
         );
         fieldToGroupByPersons.setPadding(new Insets(0, 0, 0, 20));
diff --git a/src/main/java/org/jabref/gui/groups/GroupDialogView.java b/src/main/java/org/jabref/gui/groups/GroupDialogView.java
new file mode 100644
index 00000000000..c71dcaf82c2
--- /dev/null
+++ b/src/main/java/org/jabref/gui/groups/GroupDialogView.java
@@ -0,0 +1,148 @@
+package org.jabref.gui.groups;
+
+import javafx.application.Platform;
+import javafx.fxml.FXML;
+import javafx.scene.control.ButtonType;
+import javafx.scene.control.CheckBox;
+import javafx.scene.control.ColorPicker;
+import javafx.scene.control.RadioButton;
+import javafx.scene.control.TextField;
+import javafx.scene.text.TextFlow;
+
+import org.jabref.Globals;
+import org.jabref.JabRefGUI;
+import org.jabref.gui.BasePanel;
+import org.jabref.gui.DialogService;
+import org.jabref.gui.util.BaseDialog;
+import org.jabref.gui.util.IconValidationDecorator;
+import org.jabref.logic.l10n.Localization;
+import org.jabref.model.groups.AbstractGroup;
+import org.jabref.preferences.JabRefPreferences;
+
+import com.airhacks.afterburner.views.ViewLoader;
+import de.saxsys.mvvmfx.utils.validation.visualization.ControlsFxVisualizer;
+
+public class GroupDialogView extends BaseDialog<AbstractGroup> {
+
+    // Basic Settings
+    @FXML private TextField nameField;
+    @FXML private TextField descriptionField;
+    @FXML private TextField iconField;
+    @FXML private ColorPicker colorField;
+
+    // Hierarchical Context
+    @FXML private RadioButton independentButton;
+    @FXML private RadioButton intersectionButton;
+    @FXML private RadioButton unionButton;
+
+    // Type
+    @FXML private RadioButton explicitRadioButton;
+    @FXML private RadioButton keywordsRadioButton;
+    @FXML private RadioButton searchRadioButton;
+    @FXML private RadioButton autoRadioButton;
+    @FXML private RadioButton texRadioButton;
+
+    // Option Groups
+    @FXML private TextField keyWordGroupSearchTerm;
+    @FXML private TextField keyWordGroupSearchField;
+    @FXML private CheckBox keywordGroupCaseSensitive;
+    @FXML private CheckBox keywordGroupRegExp;
+
+    @FXML private TextField searchGroupSearchExpression;
+    @FXML private CheckBox searchGroupCaseSensitive;
+    @FXML private CheckBox searchGroupRegExp;
+
+    @FXML private RadioButton autoGroupKeywordsOption;
+    @FXML private TextField autoGroupKeywordsField;
+    @FXML private TextField autoGroupKeywordsDeliminator;
+    @FXML private TextField autoGroupKeywordsHierarchicalDeliminator;
+    @FXML private RadioButton autoGroupPersonsOption;
+    @FXML private TextField autoGroupPersonsField;
+
+    @FXML private TextField texGroupFilePath;
+
+    // Description text
+    @FXML private TextFlow hintTextFlow;
+
+    private final ControlsFxVisualizer validationVisualizer = new ControlsFxVisualizer();
+    private final GroupDialogViewModel viewModel;
+
+    public GroupDialogView(DialogService dialogService, BasePanel basePanel, JabRefPreferences prefs, AbstractGroup editedGroup) {
+        viewModel = new GroupDialogViewModel(dialogService, basePanel, prefs, editedGroup);
+
+        ViewLoader.view(this)
+                  .load()
+                  .setAsDialogPane(this);
+
+        if (editedGroup == null) {
+            this.setTitle(Localization.lang("Add subgroup"));
+        } else {
+            this.setTitle(Localization.lang("Edit group"));
+        }
+
+        setResultConverter(viewModel::resultConverter);
+        getDialogPane().getButtonTypes().setAll(ButtonType.OK, ButtonType.CANCEL);
+    }
+
+    public GroupDialogView(DialogService dialogService, AbstractGroup editedGroup) {
+        this(dialogService, JabRefGUI.getMainFrame().getCurrentBasePanel(), Globals.prefs, editedGroup);
+    }
+
+    public GroupDialogView(DialogService dialogService) {
+        this(dialogService, JabRefGUI.getMainFrame().getCurrentBasePanel(), Globals.prefs, null);
+    }
+
+    @FXML
+    public void initialize() {
+        nameField.textProperty().bindBidirectional(viewModel.nameProperty());
+        descriptionField.textProperty().bindBidirectional(viewModel.descriptionProperty());
+        iconField.textProperty().bindBidirectional(viewModel.iconProperty());
+        colorField.valueProperty().bindBidirectional(viewModel.colorFieldProperty());
+
+        independentButton.selectedProperty().bindBidirectional(viewModel.hierarchyIndependentProperty());
+        intersectionButton.selectedProperty().bindBidirectional(viewModel.hierarchyIntersectionProperty());
+        unionButton.selectedProperty().bindBidirectional(viewModel.hierarchyUnionProperty());
+
+        explicitRadioButton.selectedProperty().bindBidirectional(viewModel.typeExplicitProperty());
+        keywordsRadioButton.selectedProperty().bindBidirectional(viewModel.typeKeywordsProperty());
+        searchRadioButton.selectedProperty().bindBidirectional(viewModel.typeSearchProperty());
+        autoRadioButton.selectedProperty().bindBidirectional(viewModel.typeAutoProperty());
+        texRadioButton.selectedProperty().bindBidirectional(viewModel.typeTexProperty());
+
+        keyWordGroupSearchTerm.textProperty().bindBidirectional(viewModel.keywordGroupSearchTermProperty());
+        keyWordGroupSearchField.textProperty().bindBidirectional(viewModel.keywordGroupSearchFieldProperty());
+        keywordGroupCaseSensitive.selectedProperty().bindBidirectional(viewModel.keywordGroupCaseSensitiveProperty());
+        keywordGroupRegExp.selectedProperty().bindBidirectional(viewModel.keywordGroupRegExpProperty());
+
+        searchGroupSearchExpression.textProperty().bindBidirectional(viewModel.searchGroupSearchExpressionProperty());
+        searchGroupCaseSensitive.selectedProperty().bindBidirectional(viewModel.searchGroupCaseSensitiveProperty());
+        searchGroupRegExp.selectedProperty().bindBidirectional(viewModel.searchGroupRegExpProperty());
+
+        autoGroupKeywordsOption.selectedProperty().bindBidirectional(viewModel.autoGroupKeywordsOptionProperty());
+        autoGroupKeywordsField.textProperty().bindBidirectional(viewModel.autoGroupKeywordsFieldProperty());
+        autoGroupKeywordsDeliminator.textProperty().bindBidirectional(viewModel.autoGroupKeywordsDeliminatorProperty());
+        autoGroupKeywordsHierarchicalDeliminator.textProperty().bindBidirectional(viewModel.autoGroupKeywordsHierarchicalDeliminatorProperty());
+        autoGroupPersonsOption.selectedProperty().bindBidirectional(viewModel.autoGroupPersonsOptionProperty());
+        autoGroupPersonsField.textProperty().bindBidirectional(viewModel.autoGroupPersonsFieldProperty());
+
+        texGroupFilePath.textProperty().bindBidirectional(viewModel.texGroupFilePathProperty());
+
+        hintTextFlow.accessibleTextProperty().bindBidirectional(viewModel.hintTextProperty());
+
+        validationVisualizer.setDecoration(new IconValidationDecorator());
+        Platform.runLater(() -> {
+            validationVisualizer.initVisualization(viewModel.nameValidationStatus(), nameField);
+            validationVisualizer.initVisualization(viewModel.sameNameValidationStatus(), nameField);
+            validationVisualizer.initVisualization(viewModel.searchRegexValidationStatus(), searchGroupSearchExpression);
+            validationVisualizer.initVisualization(viewModel.keywordRegexValidationStatus(), keyWordGroupSearchTerm);
+        });
+
+        // getDialogPane().lookupButton(ButtonType.OK).disableProperty().bind(viewModel.validationStatus().validProperty().not());
+    }
+
+    @FXML
+    private void texGroupBrowse() {
+        viewModel.texGroupBrowse();
+    }
+
+}
diff --git a/src/main/java/org/jabref/gui/groups/GroupDialogViewModel.java b/src/main/java/org/jabref/gui/groups/GroupDialogViewModel.java
new file mode 100644
index 00000000000..10096b70311
--- /dev/null
+++ b/src/main/java/org/jabref/gui/groups/GroupDialogViewModel.java
@@ -0,0 +1,493 @@
+package org.jabref.gui.groups;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+import java.util.regex.Pattern;
+import java.util.regex.PatternSyntaxException;
+
+import javafx.beans.property.BooleanProperty;
+import javafx.beans.property.ObjectProperty;
+import javafx.beans.property.SimpleBooleanProperty;
+import javafx.beans.property.SimpleObjectProperty;
+import javafx.beans.property.SimpleStringProperty;
+import javafx.beans.property.StringProperty;
+import javafx.scene.control.ButtonType;
+import javafx.scene.paint.Color;
+
+import org.jabref.Globals;
+import org.jabref.gui.BasePanel;
+import org.jabref.gui.DialogService;
+import org.jabref.gui.icon.IconTheme;
+import org.jabref.gui.util.FileDialogConfiguration;
+import org.jabref.logic.auxparser.DefaultAuxParser;
+import org.jabref.logic.l10n.Localization;
+import org.jabref.logic.util.StandardFileType;
+import org.jabref.logic.util.io.FileUtil;
+import org.jabref.model.database.BibDatabase;
+import org.jabref.model.entry.field.FieldFactory;
+import org.jabref.model.groups.AbstractGroup;
+import org.jabref.model.groups.AutomaticGroup;
+import org.jabref.model.groups.AutomaticKeywordGroup;
+import org.jabref.model.groups.AutomaticPersonsGroup;
+import org.jabref.model.groups.ExplicitGroup;
+import org.jabref.model.groups.GroupHierarchyType;
+import org.jabref.model.groups.GroupTreeNode;
+import org.jabref.model.groups.RegexKeywordGroup;
+import org.jabref.model.groups.SearchGroup;
+import org.jabref.model.groups.TexGroup;
+import org.jabref.model.groups.WordKeywordGroup;
+import org.jabref.model.metadata.MetaData;
+import org.jabref.model.strings.StringUtil;
+import org.jabref.preferences.JabRefPreferences;
+
+import de.saxsys.mvvmfx.utils.validation.CompositeValidator;
+import de.saxsys.mvvmfx.utils.validation.FunctionBasedValidator;
+import de.saxsys.mvvmfx.utils.validation.ValidationMessage;
+import de.saxsys.mvvmfx.utils.validation.ValidationStatus;
+import de.saxsys.mvvmfx.utils.validation.Validator;
+
+public class GroupDialogViewModel {
+
+    // Basic Settings
+    private final StringProperty nameProperty = new SimpleStringProperty("");
+    private final StringProperty descriptionProperty = new SimpleStringProperty("");
+    private final StringProperty iconProperty = new SimpleStringProperty("");
+    private final ObjectProperty<Color> colorProperty = new SimpleObjectProperty<>();
+
+    // Hierarchical Context
+    private final BooleanProperty hierarchyIndependentProperty = new SimpleBooleanProperty();
+    private final BooleanProperty hierarchyIntersectionProperty = new SimpleBooleanProperty();
+    private final BooleanProperty hierarchyUnionProperty = new SimpleBooleanProperty();
+
+    // Type
+    private final BooleanProperty typeExplicitProperty = new SimpleBooleanProperty();
+    private final BooleanProperty typeKeywordsProperty = new SimpleBooleanProperty();
+    private final BooleanProperty typeSearchProperty = new SimpleBooleanProperty();
+    private final BooleanProperty typeAutoProperty = new SimpleBooleanProperty();
+    private final BooleanProperty typeTexProperty = new SimpleBooleanProperty();
+
+    // Option Groups
+    private final StringProperty keywordGroupSearchTermProperty = new SimpleStringProperty("");
+    private final StringProperty keywordGroupSearchFieldProperty = new SimpleStringProperty("");
+    private final BooleanProperty keywordGroupCaseSensitiveProperty = new SimpleBooleanProperty();
+    private final BooleanProperty keywordGroupRegExpProperty = new SimpleBooleanProperty();
+
+    private final StringProperty searchGroupSearchExpressionProperty = new SimpleStringProperty("");
+    private final BooleanProperty searchGroupCaseSensitiveProperty = new SimpleBooleanProperty();
+    private final BooleanProperty searchGroupRegExpProperty = new SimpleBooleanProperty();
+
+    private final BooleanProperty autoGroupKeywordsOptionProperty = new SimpleBooleanProperty();
+    private final StringProperty autoGroupKeywordsFieldProperty = new SimpleStringProperty("");
+    private final StringProperty autoGroupKeywordsDelimiterProperty = new SimpleStringProperty("");
+    private final StringProperty autoGroupKeywordsHierarchicalDelimiterProperty = new SimpleStringProperty("");
+    private final BooleanProperty autoGroupPersonsOptionProperty = new SimpleBooleanProperty();
+    private final StringProperty autoGroupPersonsFieldProperty = new SimpleStringProperty("");
+
+    private final StringProperty texGroupFilePathProperty = new SimpleStringProperty("");
+
+    // Description text
+    private final StringProperty hintTextProperty = new SimpleStringProperty("");
+
+    private final Validator nameValidator;
+    private final Validator sameNameValidator;
+    private final Validator keywordRegexValidator;
+    private final Validator searchRegexValidator;
+
+    private final DialogService dialogService;
+    private final JabRefPreferences preferences;
+    private final BasePanel basePanel;
+    private final AbstractGroup editedGroup;
+
+    public GroupDialogViewModel(DialogService dialogService, BasePanel basePanel, JabRefPreferences preferences, AbstractGroup editedGroup) {
+        this.dialogService = dialogService;
+        this.preferences = preferences;
+        this.basePanel = basePanel;
+        this.editedGroup = editedGroup;
+
+        nameValidator = new FunctionBasedValidator<>(
+                nameProperty,
+                StringUtil::isNotBlank,
+                ValidationMessage.error(Localization.lang("Please enter a name for the group.")));
+
+        sameNameValidator = new FunctionBasedValidator<>(
+                nameProperty,
+                name -> {
+                    Optional<GroupTreeNode> rootGroup = basePanel.getBibDatabaseContext().getMetaData().getGroups();
+                    if (rootGroup.isPresent()) {
+                        int groupsWithSameName = rootGroup.get().findChildrenSatisfying(group -> group.getName().equals(name)).size();
+                        if ((editedGroup == null) && (groupsWithSameName > 0)) {
+                            // New group but there is already one group with the same name
+                            return false;
+                        }
+
+                        if ((editedGroup != null) && !editedGroup.getName().equals(name) && (groupsWithSameName > 0)) {
+                            // Edit group, changed name to something that is already present
+                            return false;
+                        }
+                    }
+                    return true;
+                },
+                ValidationMessage.error(Localization.lang("There exists already a group with the same name.")));
+
+        keywordRegexValidator = new FunctionBasedValidator<>(
+                keywordGroupSearchTermProperty,
+                input -> {
+                    if (!keywordGroupRegExpProperty.getValue()) {
+                        return true;
+                    }
+
+                    if (StringUtil.isNullOrEmpty(input)) {
+                        return false;
+                    }
+
+                    try {
+                        Pattern.compile(input);
+                        return true;
+                    } catch (PatternSyntaxException ignored) {
+                        return false;
+                    }
+                },
+                ValidationMessage.error(String.format("%s > %n %s %n %n %s %n %s",
+                        Localization.lang("Dynamically group entries by searching a field for a keyword"),
+                        Localization.lang("Keywords"),
+                        Localization.lang("Invalid regular expression:"),
+                        keywordGroupSearchTermProperty.getValue())));
+
+        searchRegexValidator = new FunctionBasedValidator<>(
+                searchGroupSearchExpressionProperty,
+                input -> {
+                    if (!searchGroupRegExpProperty.getValue()) {
+                        return true;
+                    }
+
+                    if (StringUtil.isNullOrEmpty(input)) {
+                        return false;
+                    }
+
+                    try {
+                        Pattern.compile(input);
+                        return true;
+                    } catch (PatternSyntaxException ignored) {
+                        return false;
+                    }
+                },
+                ValidationMessage.error(String.format("%s > %n %s %n %n %s %n %s",
+                        Localization.lang("Dynamically group entries by a free-form search expression"),
+                        Localization.lang("Keywords"),
+                        Localization.lang("Invalid regular expression:"),
+                        searchGroupSearchExpressionProperty.getValue())));
+
+        setValues();
+    }
+
+    public AbstractGroup resultConverter(ButtonType button) {
+        if (button == ButtonType.OK) {
+            AbstractGroup resultingGroup = null;
+            try {
+                String groupName = nameProperty.getValue().trim();
+                if (typeExplicitProperty.getValue()) {
+                    Character keywordDelimiter = Globals.prefs.getKeywordDelimiter();
+                    if (groupName.contains(Character.toString(keywordDelimiter))) {
+                        dialogService.showWarningDialogAndWait(null, Localization.lang("The group name contains the keyword separator \"%0\" and thus probably does not work as expected.", Character.toString(keywordDelimiter)));
+                    }
+
+                    Optional<GroupTreeNode> rootGroup = basePanel.getBibDatabaseContext().getMetaData().getGroups();
+                    if (rootGroup.isPresent()) {
+                        int groupsWithSameName = rootGroup.get().findChildrenSatisfying(group -> group.getName().equals(groupName)).size();
+                        boolean warnAboutSameName = false;
+                        if ((editedGroup == null) && (groupsWithSameName > 0)) {
+                            // New group but there is already one group with the same name
+                            warnAboutSameName = true;
+                        }
+                        if ((editedGroup != null) && !editedGroup.getName().equals(groupName) && (groupsWithSameName > 0)) {
+                            // Edit group, changed name to something that is already present
+                            warnAboutSameName = true;
+                        }
+
+                        if (warnAboutSameName) {
+                            dialogService.showErrorDialogAndWait(Localization.lang("There exists already a group with the same name.", Character.toString(keywordDelimiter)));
+                            return null;
+                        }
+                    }
+
+                    resultingGroup = new ExplicitGroup(groupName, getContext(),
+                            keywordDelimiter);
+                } else if (typeKeywordsProperty.getValue()) {
+                    if (keywordGroupRegExpProperty.getValue()) {
+                        resultingGroup = new RegexKeywordGroup(
+                                groupName,
+                                getContext(),
+                                FieldFactory.parseField(keywordGroupSearchFieldProperty.getValue().trim()),
+                                keywordGroupSearchTermProperty.getValue().trim(),
+                                keywordGroupCaseSensitiveProperty.getValue());
+                    } else {
+                        resultingGroup = new WordKeywordGroup(
+                                groupName,
+                                getContext(),
+                                FieldFactory.parseField(keywordGroupSearchFieldProperty.getValue().trim()),
+                                keywordGroupSearchTermProperty.getValue().trim(),
+                                keywordGroupCaseSensitiveProperty.getValue(),
+                                Globals.prefs.getKeywordDelimiter(),
+                                false);
+                    }
+                } else if (typeSearchProperty.getValue()) {
+                    resultingGroup = new SearchGroup(
+                            groupName,
+                            getContext(),
+                            searchGroupSearchExpressionProperty.getValue().trim(),
+                            searchGroupCaseSensitiveProperty.getValue(),
+                            searchGroupRegExpProperty.getValue());
+                } else if (typeAutoProperty.getValue()) {
+                    if (autoGroupKeywordsOptionProperty.getValue()) {
+                        resultingGroup = new AutomaticKeywordGroup(
+                                groupName,
+                                getContext(),
+                                FieldFactory.parseField(autoGroupKeywordsFieldProperty.getValue().trim()),
+                                autoGroupKeywordsDelimiterProperty.getValue().charAt(0),
+                                autoGroupKeywordsHierarchicalDelimiterProperty.getValue().charAt(0));
+                    } else {
+                        resultingGroup = new AutomaticPersonsGroup(
+                                groupName,
+                                getContext(),
+                                FieldFactory.parseField(autoGroupPersonsFieldProperty.getValue().trim()));
+                    }
+                } else if (typeTexProperty.getValue()) {
+                    resultingGroup = TexGroup.create(
+                            groupName,
+                            getContext(),
+                            Paths.get(texGroupFilePathProperty.getValue().trim()),
+                            new DefaultAuxParser(new BibDatabase()),
+                            Globals.getFileUpdateMonitor(),
+                            basePanel.getBibDatabaseContext().getMetaData());
+                }
+
+                if (resultingGroup != null) {
+                    resultingGroup.setColor(colorProperty.getValue());
+                    resultingGroup.setDescription(descriptionProperty.getValue());
+                    resultingGroup.setIconName(iconProperty.getValue());
+                    return resultingGroup;
+                } else {
+                    return null;
+                }
+
+            } catch (IllegalArgumentException | IOException exception) {
+                dialogService.showErrorDialogAndWait(exception.getLocalizedMessage(), exception);
+                return null;
+            }
+        }
+        return null;
+    }
+
+    public void setValues() {
+        if (editedGroup == null) {
+            // creating new group -> defaults!
+            colorProperty.setValue(IconTheme.getDefaultGroupColor());
+            typeExplicitProperty.setValue(true);
+            setContext(GroupHierarchyType.INDEPENDENT);
+        } else {
+            nameProperty.setValue(editedGroup.getName());
+            colorProperty.setValue(editedGroup.getColor().orElse(IconTheme.getDefaultGroupColor()));
+            descriptionProperty.setValue(editedGroup.getDescription().orElse(""));
+            iconProperty.setValue(editedGroup.getIconName().orElse(""));
+            setContext(editedGroup.getHierarchicalContext());
+
+            if (editedGroup.getClass() == WordKeywordGroup.class) {
+                WordKeywordGroup group = (WordKeywordGroup) editedGroup;
+                keywordGroupSearchFieldProperty.setValue(group.getSearchField().getName());
+                keywordGroupSearchTermProperty.setValue(group.getSearchExpression());
+                keywordGroupCaseSensitiveProperty.setValue(group.isCaseSensitive());
+                keywordGroupRegExpProperty.setValue(false);
+
+                typeExplicitProperty.setValue(false);
+                typeKeywordsProperty.setValue(true);
+                typeSearchProperty.setValue(false);
+                typeAutoProperty.setValue(false);
+                typeTexProperty.setValue(false);
+            } else if (editedGroup.getClass() == RegexKeywordGroup.class) {
+                RegexKeywordGroup group = (RegexKeywordGroup) editedGroup;
+                keywordGroupSearchFieldProperty.setValue(group.getSearchField().getName());
+                keywordGroupSearchTermProperty.setValue(group.getSearchExpression());
+                keywordGroupCaseSensitiveProperty.setValue(group.isCaseSensitive());
+                keywordGroupRegExpProperty.setValue(true);
+
+                typeExplicitProperty.setValue(false);
+                typeKeywordsProperty.setValue(true);
+                typeSearchProperty.setValue(false);
+                typeAutoProperty.setValue(false);
+                typeTexProperty.setValue(false);
+            } else if (editedGroup.getClass() == SearchGroup.class) {
+                SearchGroup group = (SearchGroup) editedGroup;
+                searchGroupSearchExpressionProperty.setValue(group.getSearchExpression());
+                searchGroupCaseSensitiveProperty.setValue(group.isCaseSensitive());
+                searchGroupRegExpProperty.setValue(group.isRegularExpression());
+
+                typeExplicitProperty.setValue(false);
+                typeKeywordsProperty.setValue(false);
+                typeSearchProperty.setValue(true);
+                typeAutoProperty.setValue(false);
+                typeTexProperty.setValue(false);
+            } else if (editedGroup.getClass() == ExplicitGroup.class) {
+                typeExplicitProperty.setValue(true);
+                typeKeywordsProperty.setValue(false);
+                typeSearchProperty.setValue(false);
+                typeAutoProperty.setValue(false);
+            } else if (editedGroup instanceof AutomaticGroup) {
+                typeExplicitProperty.setValue(false);
+                typeKeywordsProperty.setValue(false);
+                typeSearchProperty.setValue(false);
+                typeAutoProperty.setValue(true);
+                typeTexProperty.setValue(false);
+
+                if (editedGroup.getClass() == AutomaticKeywordGroup.class) {
+                    AutomaticKeywordGroup group = (AutomaticKeywordGroup) editedGroup;
+                    autoGroupKeywordsDelimiterProperty.setValue(group.getKeywordDelimiter().toString());
+                    autoGroupKeywordsHierarchicalDelimiterProperty.setValue(group.getKeywordHierarchicalDelimiter().toString());
+                    autoGroupKeywordsFieldProperty.setValue(group.getField().getName());
+                } else if (editedGroup.getClass() == AutomaticPersonsGroup.class) {
+                    AutomaticPersonsGroup group = (AutomaticPersonsGroup) editedGroup;
+                    autoGroupPersonsFieldProperty.setValue(group.getField().getName());
+                }
+            } else if (editedGroup.getClass() == TexGroup.class) {
+                typeExplicitProperty.setValue(false);
+                typeKeywordsProperty.setValue(false);
+                typeSearchProperty.setValue(false);
+                typeAutoProperty.setValue(false);
+                typeTexProperty.setValue(true);
+
+                TexGroup group = (TexGroup) editedGroup;
+                texGroupFilePathProperty.setValue(group.getFilePath().toString());
+            }
+        }
+    }
+
+    public void texGroupBrowse() {
+        FileDialogConfiguration fileDialogConfiguration = new FileDialogConfiguration.Builder()
+                .addExtensionFilter(StandardFileType.AUX)
+                .withDefaultExtension(StandardFileType.AUX)
+                .withInitialDirectory(Globals.prefs.get(JabRefPreferences.WORKING_DIRECTORY)).build();
+        dialogService.showFileOpenDialog(fileDialogConfiguration).ifPresent(file -> texGroupFilePathProperty.setValue(relativise(file.toAbsolutePath()).toString()));
+    }
+
+    private Path relativise(Path path) {
+        List<Path> fileDirectories = getFileDirectoriesAsPaths();
+        return FileUtil.relativize(path, fileDirectories);
+    }
+
+    private List<Path> getFileDirectoriesAsPaths() {
+        List<Path> fileDirs = new ArrayList<>();
+        MetaData metaData = basePanel.getBibDatabaseContext().getMetaData();
+        metaData.getLaTexFileDirectory(preferences.getFilePreferences().getUser()).ifPresent(fileDirs::add);
+
+        return fileDirs;
+    }
+
+    public ValidationStatus validationStatus() {
+        CompositeValidator validator = new CompositeValidator();
+
+        validator.addValidators(nameValidator);
+        validator.addValidators(sameNameValidator);
+
+        if (typeSearchProperty.getValue()) {
+            validator.addValidators(searchRegexValidator);
+        }
+
+        if (typeKeywordsProperty.getValue()) {
+            validator.addValidators(keywordRegexValidator);
+        }
+
+        return validator.getValidationStatus();
+    }
+
+    public ValidationStatus nameValidationStatus() { return nameValidator.getValidationStatus(); }
+
+    public ValidationStatus sameNameValidationStatus() { return sameNameValidator.getValidationStatus(); }
+
+    public ValidationStatus searchRegexValidationStatus() { return searchRegexValidator.getValidationStatus(); }
+
+    public ValidationStatus keywordRegexValidationStatus() { return keywordRegexValidator.getValidationStatus(); }
+
+    private GroupHierarchyType getContext() {
+        if (hierarchyIndependentProperty.getValue()) {
+            return GroupHierarchyType.INDEPENDENT;
+        }
+        if (hierarchyIntersectionProperty.getValue()) {
+            return GroupHierarchyType.REFINING;
+        }
+        if (hierarchyUnionProperty.getValue()) {
+            return GroupHierarchyType.INCLUDING;
+        }
+        return GroupHierarchyType.INDEPENDENT; // default
+    }
+
+    private void setContext(GroupHierarchyType context) {
+        switch (context) {
+            case INDEPENDENT:
+                hierarchyIndependentProperty.setValue(true);
+                break;
+            case REFINING:
+                hierarchyIntersectionProperty.setValue(true);
+                break;
+            case INCLUDING:
+                hierarchyUnionProperty.setValue(true);
+                break;
+        }
+    }
+
+    public StringProperty nameProperty() { return nameProperty; }
+
+    public StringProperty descriptionProperty() { return descriptionProperty; }
+
+    public StringProperty iconProperty() { return iconProperty; }
+
+    public ObjectProperty<Color> colorFieldProperty() { return colorProperty; }
+
+    public BooleanProperty hierarchyIndependentProperty() { return hierarchyIndependentProperty; }
+
+    public BooleanProperty hierarchyIntersectionProperty() { return hierarchyIntersectionProperty; }
+
+    public BooleanProperty hierarchyUnionProperty() { return hierarchyUnionProperty; }
+
+    public BooleanProperty typeExplicitProperty() { return typeExplicitProperty; }
+
+    public BooleanProperty typeKeywordsProperty() { return typeKeywordsProperty; }
+
+    public BooleanProperty typeSearchProperty() { return typeSearchProperty; }
+
+    public BooleanProperty typeAutoProperty() { return typeAutoProperty; }
+
+    public BooleanProperty typeTexProperty() { return typeTexProperty; }
+
+    public StringProperty keywordGroupSearchTermProperty() { return keywordGroupSearchTermProperty; }
+
+    public StringProperty keywordGroupSearchFieldProperty() { return keywordGroupSearchFieldProperty; }
+
+    public BooleanProperty keywordGroupCaseSensitiveProperty() { return keywordGroupCaseSensitiveProperty; }
+
+    public BooleanProperty keywordGroupRegExpProperty() { return keywordGroupRegExpProperty; }
+
+    public StringProperty searchGroupSearchExpressionProperty() { return searchGroupSearchExpressionProperty; }
+
+    public BooleanProperty searchGroupCaseSensitiveProperty() { return searchGroupCaseSensitiveProperty; }
+
+    public BooleanProperty searchGroupRegExpProperty() { return searchGroupRegExpProperty; }
+
+    public BooleanProperty autoGroupKeywordsOptionProperty() { return autoGroupKeywordsOptionProperty; }
+
+    public StringProperty autoGroupKeywordsFieldProperty() { return autoGroupKeywordsFieldProperty; }
+
+    public StringProperty autoGroupKeywordsDeliminatorProperty() { return autoGroupKeywordsDelimiterProperty; }
+
+    public StringProperty autoGroupKeywordsHierarchicalDeliminatorProperty() { return autoGroupKeywordsHierarchicalDelimiterProperty; }
+
+    public BooleanProperty autoGroupPersonsOptionProperty() { return autoGroupPersonsOptionProperty; }
+
+    public StringProperty autoGroupPersonsFieldProperty() { return autoGroupPersonsFieldProperty; }
+
+    public StringProperty texGroupFilePathProperty() { return texGroupFilePathProperty; }
+
+    public StringProperty hintTextProperty() { return hintTextProperty; }
+}
diff --git a/src/main/java/org/jabref/gui/groups/GroupTreeViewModel.java b/src/main/java/org/jabref/gui/groups/GroupTreeViewModel.java
index 47ae8b58c62..85b710f8539 100644
--- a/src/main/java/org/jabref/gui/groups/GroupTreeViewModel.java
+++ b/src/main/java/org/jabref/gui/groups/GroupTreeViewModel.java
@@ -142,7 +142,7 @@ private void onActiveDatabaseChanged(Optional<BibDatabaseContext> newDatabase) {
      * Opens "New Group Dialog" and add the resulting group to the specified group
      */
     public void addNewSubgroup(GroupNodeViewModel parent) {
-        Optional<AbstractGroup> newGroup = dialogService.showCustomDialogAndWait(new GroupDialog(dialogService));
+        Optional<AbstractGroup> newGroup = dialogService.showCustomDialogAndWait(new GroupDialogView(dialogService));
         newGroup.ifPresent(group -> {
             parent.addSubgroup(group);
 
@@ -167,7 +167,7 @@ private void writeGroupChangesToMetaData() {
      */
     public void editGroup(GroupNodeViewModel oldGroup) {
         Optional<AbstractGroup> newGroup = dialogService
-                .showCustomDialogAndWait(new GroupDialog(dialogService, oldGroup.getGroupNode().getGroup()));
+                .showCustomDialogAndWait(new GroupDialogView(dialogService, oldGroup.getGroupNode().getGroup()));
         newGroup.ifPresent(group -> {
             // TODO: Keep assignments
             boolean keepPreviousAssignments = dialogService.showConfirmationDialogAndWait(
diff --git a/src/main/resources/l10n/JabRef_en.properties b/src/main/resources/l10n/JabRef_en.properties
index 5b80f5641d1..ccc385c0d6b 100644
--- a/src/main/resources/l10n/JabRef_en.properties
+++ b/src/main/resources/l10n/JabRef_en.properties
@@ -348,7 +348,7 @@ field=field
 Field\ name=Field name
 Field\ names\ are\ not\ allowed\ to\ contain\ white\ space\ or\ the\ following\ characters=Field names are not allowed to contain white space or the following characters
 
-Field\ to\ group\ by=Field to group by
+Field\ to\ group\ by\:=Field to group by:
 
 File=File
 
@@ -495,6 +495,8 @@ keys\ in\ library=keys in library
 
 Keyword=Keyword
 
+Keywords=Keywords
+
 Label=Label
 
 Language=Language
@@ -2099,3 +2101,5 @@ Select\ all\ changes\ on\ the\ right=Select all changes on the right
 Dismiss=Dismiss
 Mark\ all\ changes\ as\ accepted=Mark all changes as accepted
 Unmark\ all\ changes=Unmark all changes
+
+Invalid\ regular\ expression\:=Invalid regular expression:

From 8351736a6d4afb27909e86d7a6b2e4362798bb38 Mon Sep 17 00:00:00 2001
From: Carl Christian Snethlage <cc.snethlage@gmail.com>
Date: Sun, 12 Jan 2020 17:15:08 +0100
Subject: [PATCH 2/9] Added hintTextFlow, some rewording and changed the
 hierarchicalContext RadioButtons to a ComboBox

---
 src/main/java/org/jabref/gui/Base.css         |   4 +
 .../org/jabref/gui/groups/GroupDialog.fxml    | 154 ++++++-----
 .../jabref/gui/groups/GroupDialogView.java    | 242 ++++++++++++++++--
 .../gui/groups/GroupDialogViewModel.java      | 234 ++++++++---------
 src/main/resources/l10n/JabRef_en.properties  |  13 +-
 5 files changed, 447 insertions(+), 200 deletions(-)

diff --git a/src/main/java/org/jabref/gui/Base.css b/src/main/java/org/jabref/gui/Base.css
index 8a99e653b8a..8392be71d72 100644
--- a/src/main/java/org/jabref/gui/Base.css
+++ b/src/main/java/org/jabref/gui/Base.css
@@ -1121,3 +1121,7 @@ We want to have a look that matches our icons in the tool-bar */
     -fx-font-weight: bold;
     -fx-label-padding: 5 0 10 10;
 }
+
+TextFlow * {
+    -fx-fill: -fx-text-background-color;
+}
diff --git a/src/main/java/org/jabref/gui/groups/GroupDialog.fxml b/src/main/java/org/jabref/gui/groups/GroupDialog.fxml
index e1a106660d1..ca74c485979 100644
--- a/src/main/java/org/jabref/gui/groups/GroupDialog.fxml
+++ b/src/main/java/org/jabref/gui/groups/GroupDialog.fxml
@@ -5,7 +5,7 @@
 
 <?import javafx.geometry.Insets?>
 <?import javafx.scene.text.TextFlow?>
-<DialogPane prefHeight="300.0" prefWidth="700.0" xmlns="http://javafx.com/javafx/10.0.2-internal"
+<DialogPane prefHeight="300.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/10.0.2-internal"
             xmlns:fx="http://javafx.com/fxml/1" fx:controller="org.jabref.gui.groups.GroupDialogView">
     <content>
         <fx:define>
@@ -13,65 +13,87 @@
             <ToggleGroup fx:id="type"/>
             <ToggleGroup fx:id="autoGroupOptions"/>
         </fx:define>
-        <VBox>
-            <SplitPane dividerPositions="0.5">
-                <VBox spacing="10.0" minWidth="150">
-                    <padding>
-                        <Insets bottom="4.0" left="4.0" right="4.0" top="4.0"/>
-                    </padding>
-                    <Label styleClass="sectionHeader" text="%General"/>
-                    <Label text="%Name"/>
-                    <TextField fx:id="nameField"/>
-                    <Label text="%Description"/>
-                    <TextField fx:id="descriptionField"/>
-                    <HBox spacing="10.0">
-                        <VBox HBox.hgrow="ALWAYS">
-                            <Label text="%Icon"/>
-                            <TextField fx:id="iconField"/>
-                        </VBox>
-                        <VBox layoutX="10.0" layoutY="10.0" HBox.hgrow="ALWAYS">
-                            <Label text="%Color"/>
-                            <ColorPicker fx:id="colorField"/>
-                        </VBox>
-                    </HBox>
+        <VBox spacing="10.0" minWidth="200">
+            <padding>
+                <Insets bottom="4.0" left="4.0" right="4.0" top="4.0"/>
+            </padding>
+            <VBox>
+                <Label text="%Name"/>
+                <TextField fx:id="nameField"/>
+            </VBox>
+            <VBox>
+                <Label text="%Description"/>
+                <TextField fx:id="descriptionField"/>
+            </VBox>
+            <HBox spacing="10.0">
+                <VBox HBox.hgrow="ALWAYS">
+                    <Label text="%Icon"/>
+                    <TextField fx:id="iconField"/>
+                </VBox>
+                <VBox layoutX="10.0" layoutY="10.0" minWidth="130.0" maxWidth="130.0" prefWidth="130.0">
+                    <Label text="%Color"/>
+                    <ColorPicker fx:id="colorField"/>
+                </VBox>
+                <VBox>
                     <Label text="%Hierarchical context"/>
-                    <RadioButton fx:id="independentButton" toggleGroup="$hierarchicalContext" wrapText="true"
-                                 text="%Independent group: When selected, view only this group's entries"/>
-                    <RadioButton fx:id="intersectionButton" toggleGroup="$hierarchicalContext" wrapText="true"
-                                 text="%Refine supergroup: When selected, view entries contained in both this group and its supergroup"/>
-                    <RadioButton fx:id="unionButton" toggleGroup="$hierarchicalContext" wrapText="true"
-                                 text="%Include subgroups: When selected, view entries contained in this group or its subgroups"/>
-                    <Label text="%Type"/>
+                    <ComboBox fx:id="hierarchicalContextCombo" minWidth="130.0" maxWidth="130.0" prefWidth="130.0"/>
+                </VBox>
+            </HBox>
+            <Separator/>
+            <HBox spacing="4.0">
+                <VBox spacing="4.0">
+                    <Label text="%Collect by"/>
                     <RadioButton fx:id="explicitRadioButton" toggleGroup="$type" wrapText="true"
-                                 text="%Statically group entries by manual assignment"/>
+                                 text="%Explicit selection">
+                        <tooltip>
+                            <Tooltip text="%Statically group entries by manual assignment"/>
+                        </tooltip>
+                    </RadioButton>
                     <RadioButton fx:id="keywordsRadioButton" toggleGroup="$type" wrapText="true"
-                                 text="%Dynamically group entries by searching a field for a keyword"/>
+                                 text="%Searching for keywords">
+                        <tooltip>
+                            <Tooltip text="%Dynamically group entries by searching a field for a keyword"/>
+                        </tooltip>
+                    </RadioButton>
                     <RadioButton fx:id="searchRadioButton" toggleGroup="$type" wrapText="true"
-                                 text="%Dynamically group entries by a free-form search expression"/>
+                                 text="%Free search expression">
+                        <tooltip>
+                            <Tooltip text="%Dynamically group entries by a free-form search expression"/>
+                        </tooltip>
+                    </RadioButton>
                     <RadioButton fx:id="autoRadioButton" toggleGroup="$type" wrapText="true"
-                                 text="%Automatically create groups"/>
+                                 text="%Specified keywords">
+                        <tooltip>
+                            <Tooltip text="%Automatically create groups"/>
+                        </tooltip>
+                    </RadioButton>
                     <RadioButton fx:id="texRadioButton" toggleGroup="$type" wrapText="true"
-                                 text="%Group containing entries cited in a given TeX file"/>
+                                 text="%Cited entries">
+                        <tooltip>
+                            <Tooltip text="%Group containing entries cited in a given TeX file"/>
+                        </tooltip>
+                    </RadioButton>
                 </VBox>
-                <VBox minWidth="150">
-                    <padding>
-                        <Insets bottom="4.0" left="4.0" right="4.0" top="4.0"/>
-                    </padding>
-                    <Label styleClass="sectionHeader" text="%Options"/>
+                <Separator orientation="VERTICAL"/>
+                <VBox HBox.hgrow="ALWAYS">
                     <StackPane>
                         <VBox visible="${keywordsRadioButton.selected}" spacing="10.0">
                             <Label text="%Field"/>
-                            <TextField fx:id="keyWordGroupSearchTerm"/>
+                            <TextField fx:id="keywordGroupSearchField"/>
                             <Label text="%Keyword"/>
-                            <TextField fx:id="keyWordGroupSearchField"/>
-                            <CheckBox fx:id="keywordGroupCaseSensitive" text="Case sensitive"/>
-                            <CheckBox fx:id="keywordGroupRegExp" text="Regular expression"/>
+                            <TextField fx:id="keywordGroupSearchTerm"/>
+                            <HBox alignment="CENTER" spacing="10.0">
+                                <CheckBox fx:id="keywordGroupCaseSensitive" text="Case sensitive"/>
+                                <CheckBox fx:id="keywordGroupRegex" text="Regular expression"/>
+                            </HBox>
                         </VBox>
                         <VBox visible="${searchRadioButton.selected}" spacing="10.0">
                             <Label text="%Search expression"/>
-                            <TextField fx:id="searchGroupSearchExpression"/>
-                            <CheckBox fx:id="searchGroupCaseSensitive" text="Case sensitive"/>
-                            <CheckBox fx:id="searchGroupRegExp" text="Regular expression"/>
+                            <TextField fx:id="searchGroupSearchTerm"/>
+                            <HBox alignment="CENTER" spacing="10.0">
+                                <CheckBox fx:id="searchGroupCaseSensitive" text="Case sensitive"/>
+                                <CheckBox fx:id="searchGroupRegex" text="Regular expression"/>
+                            </HBox>
                         </VBox>
                         <VBox visible="${autoRadioButton.selected}" spacing="10.0">
                             <RadioButton fx:id="autoGroupKeywordsOption" toggleGroup="$autoGroupOptions"
@@ -80,25 +102,36 @@
                                 <padding>
                                     <Insets left="20.0"/>
                                 </padding>
-                                <Label text="%Field to group by:"/>
-                                <TextField fx:id="autoGroupKeywordsField"
-                                           disable="${!autoGroupKeywordsOption.selected}"/>
-                                <Label text="%Use the following delimiter character(s):"/>
                                 <HBox spacing="10.0">
-                                    <TextField fx:id="autoGroupKeywordsDeliminator"
-                                               disable="${!autoGroupKeywordsOption.selected}"/>
-                                    <TextField fx:id="autoGroupKeywordsHierarchicalDeliminator"
-                                               disable="${!autoGroupKeywordsOption.selected}"/>
+                                    <VBox HBox.hgrow="ALWAYS">
+                                        <Label text="%Field to group by:"/>
+                                        <TextField fx:id="autoGroupKeywordsField"
+                                                   disable="${!autoGroupKeywordsOption.selected}"/>
+                                    </VBox>
+                                    <VBox>
+                                        <Label text="%Delimiter character(s):"/>
+                                        <HBox spacing="10.0">
+                                            <TextField fx:id="autoGroupKeywordsDeliminator" prefWidth="50.0"
+                                                       disable="${!autoGroupKeywordsOption.selected}"/>
+                                            <TextField fx:id="autoGroupKeywordsHierarchicalDeliminator" prefWidth="50.0"
+                                                       disable="${!autoGroupKeywordsOption.selected}"/>
+                                        </HBox>
+                                    </VBox>
                                 </HBox>
                             </VBox>
                             <RadioButton fx:id="autoGroupPersonsOption" toggleGroup="$autoGroupOptions"
-                                         text="Generate groups from keywords in a BibTeX field"/>
-                            <Label text="%Field to group by:"/>
-                            <TextField fx:id="autoGroupPersonsField" disable="${!autoGroupPersonsOption.selected}"/>
+                                         text="Generate groups for author last names"/>
+                            <VBox>
+                                <padding>
+                                    <Insets left="20.0"/>
+                                </padding>
+                                <Label text="%Field to group by:"/>
+                                <TextField fx:id="autoGroupPersonsField" disable="${!autoGroupPersonsOption.selected}"/>
+                            </VBox>
                         </VBox>
                         <VBox visible="${texRadioButton.selected}" spacing="10.0">
                             <Label text="%Aux file"/>
-                            <VBox spacing="10.0">
+                            <VBox>
                                 <padding>
                                     <Insets left="20.0"/>
                                 </padding>
@@ -110,9 +143,8 @@
                         </VBox>
                     </StackPane>
                 </VBox>
-            </SplitPane>
-            <TextFlow fx:id="hintTextFlow" VBox.vgrow="ALWAYS"
-                      minHeight="120" minWidth="400"/>
+            </HBox>
+            <TextFlow fx:id="hintTextFlow" VBox.vgrow="ALWAYS" minHeight="100.0" maxHeight="100.0" prefHeight="100.0"/>
         </VBox>
     </content>
 </DialogPane>
diff --git a/src/main/java/org/jabref/gui/groups/GroupDialogView.java b/src/main/java/org/jabref/gui/groups/GroupDialogView.java
index c71dcaf82c2..5ac9f094532 100644
--- a/src/main/java/org/jabref/gui/groups/GroupDialogView.java
+++ b/src/main/java/org/jabref/gui/groups/GroupDialogView.java
@@ -1,22 +1,37 @@
 package org.jabref.gui.groups;
 
+import java.util.ArrayList;
+import java.util.regex.Pattern;
+import java.util.regex.PatternSyntaxException;
+
 import javafx.application.Platform;
+import javafx.event.ActionEvent;
 import javafx.fxml.FXML;
+import javafx.scene.Node;
 import javafx.scene.control.ButtonType;
 import javafx.scene.control.CheckBox;
 import javafx.scene.control.ColorPicker;
+import javafx.scene.control.ComboBox;
 import javafx.scene.control.RadioButton;
 import javafx.scene.control.TextField;
+import javafx.scene.input.KeyEvent;
+import javafx.scene.text.Text;
 import javafx.scene.text.TextFlow;
 
 import org.jabref.Globals;
 import org.jabref.JabRefGUI;
 import org.jabref.gui.BasePanel;
 import org.jabref.gui.DialogService;
+import org.jabref.gui.search.rules.describer.SearchDescribers;
 import org.jabref.gui.util.BaseDialog;
 import org.jabref.gui.util.IconValidationDecorator;
+import org.jabref.gui.util.TooltipTextUtil;
+import org.jabref.gui.util.ViewModelListCellFactory;
 import org.jabref.logic.l10n.Localization;
+import org.jabref.logic.search.SearchQuery;
 import org.jabref.model.groups.AbstractGroup;
+import org.jabref.model.groups.GroupHierarchyType;
+import org.jabref.model.strings.StringUtil;
 import org.jabref.preferences.JabRefPreferences;
 
 import com.airhacks.afterburner.views.ViewLoader;
@@ -29,11 +44,7 @@ public class GroupDialogView extends BaseDialog<AbstractGroup> {
     @FXML private TextField descriptionField;
     @FXML private TextField iconField;
     @FXML private ColorPicker colorField;
-
-    // Hierarchical Context
-    @FXML private RadioButton independentButton;
-    @FXML private RadioButton intersectionButton;
-    @FXML private RadioButton unionButton;
+    @FXML private ComboBox<GroupHierarchyType> hierarchicalContextCombo;
 
     // Type
     @FXML private RadioButton explicitRadioButton;
@@ -43,14 +54,14 @@ public class GroupDialogView extends BaseDialog<AbstractGroup> {
     @FXML private RadioButton texRadioButton;
 
     // Option Groups
-    @FXML private TextField keyWordGroupSearchTerm;
-    @FXML private TextField keyWordGroupSearchField;
+    @FXML private TextField keywordGroupSearchTerm;
+    @FXML private TextField keywordGroupSearchField;
     @FXML private CheckBox keywordGroupCaseSensitive;
-    @FXML private CheckBox keywordGroupRegExp;
+    @FXML private CheckBox keywordGroupRegex;
 
-    @FXML private TextField searchGroupSearchExpression;
+    @FXML private TextField searchGroupSearchTerm;
     @FXML private CheckBox searchGroupCaseSensitive;
-    @FXML private CheckBox searchGroupRegExp;
+    @FXML private CheckBox searchGroupRegex;
 
     @FXML private RadioButton autoGroupKeywordsOption;
     @FXML private TextField autoGroupKeywordsField;
@@ -67,8 +78,11 @@ public class GroupDialogView extends BaseDialog<AbstractGroup> {
     private final ControlsFxVisualizer validationVisualizer = new ControlsFxVisualizer();
     private final GroupDialogViewModel viewModel;
 
+    private final boolean showHints;
+
     public GroupDialogView(DialogService dialogService, BasePanel basePanel, JabRefPreferences prefs, AbstractGroup editedGroup) {
         viewModel = new GroupDialogViewModel(dialogService, basePanel, prefs, editedGroup);
+        this.showHints = prefs.getBoolean(JabRefPreferences.SHOW_ADVANCED_HINTS);
 
         ViewLoader.view(this)
                   .load()
@@ -80,8 +94,16 @@ public GroupDialogView(DialogService dialogService, BasePanel basePanel, JabRefP
             this.setTitle(Localization.lang("Edit group"));
         }
 
+        if (showHints) {
+            hintTextFlow.setPrefHeight(0d);
+        }
+        hintTextFlow.setVisible(showHints);
+
         setResultConverter(viewModel::resultConverter);
+
         getDialogPane().getButtonTypes().setAll(ButtonType.OK, ButtonType.CANCEL);
+
+        getDialogPane().getScene().getWindow().sizeToScene();
     }
 
     public GroupDialogView(DialogService dialogService, AbstractGroup editedGroup) {
@@ -92,16 +114,42 @@ public GroupDialogView(DialogService dialogService) {
         this(dialogService, JabRefGUI.getMainFrame().getCurrentBasePanel(), Globals.prefs, null);
     }
 
+    private String getHierarchyDisplayText(GroupHierarchyType type) {
+        switch (type) {
+            case INCLUDING:
+                return Localization.lang("Union");
+            case REFINING:
+                return Localization.lang("Intersection");
+            default:
+            case INDEPENDENT:
+                return Localization.lang("Independent");
+        }
+    }
+
+    private String getHierarchyToolTip(GroupHierarchyType type) {
+        switch (type) {
+            case INCLUDING:
+                return Localization.lang("Include subgroups: When selected, view entries contained in this group or its subgroups");
+            case REFINING:
+                return Localization.lang("Refine supergroup: When selected, view entries contained in both this group and its supergroup");
+            default:
+            case INDEPENDENT:
+                return Localization.lang("Independent group: When selected, view only this group's entries");
+        }
+    }
+
     @FXML
     public void initialize() {
         nameField.textProperty().bindBidirectional(viewModel.nameProperty());
         descriptionField.textProperty().bindBidirectional(viewModel.descriptionProperty());
         iconField.textProperty().bindBidirectional(viewModel.iconProperty());
         colorField.valueProperty().bindBidirectional(viewModel.colorFieldProperty());
-
-        independentButton.selectedProperty().bindBidirectional(viewModel.hierarchyIndependentProperty());
-        intersectionButton.selectedProperty().bindBidirectional(viewModel.hierarchyIntersectionProperty());
-        unionButton.selectedProperty().bindBidirectional(viewModel.hierarchyUnionProperty());
+        hierarchicalContextCombo.itemsProperty().bind(viewModel.groupHierarchyListProperty());
+        new ViewModelListCellFactory<GroupHierarchyType>()
+                .withText(this::getHierarchyDisplayText)
+                .withStringTooltip(this::getHierarchyToolTip)
+                .install(hierarchicalContextCombo);
+        hierarchicalContextCombo.valueProperty().bindBidirectional(viewModel.groupHierarchySelectedProperty());
 
         explicitRadioButton.selectedProperty().bindBidirectional(viewModel.typeExplicitProperty());
         keywordsRadioButton.selectedProperty().bindBidirectional(viewModel.typeKeywordsProperty());
@@ -109,14 +157,14 @@ public void initialize() {
         autoRadioButton.selectedProperty().bindBidirectional(viewModel.typeAutoProperty());
         texRadioButton.selectedProperty().bindBidirectional(viewModel.typeTexProperty());
 
-        keyWordGroupSearchTerm.textProperty().bindBidirectional(viewModel.keywordGroupSearchTermProperty());
-        keyWordGroupSearchField.textProperty().bindBidirectional(viewModel.keywordGroupSearchFieldProperty());
+        keywordGroupSearchTerm.textProperty().bindBidirectional(viewModel.keywordGroupSearchTermProperty());
+        keywordGroupSearchField.textProperty().bindBidirectional(viewModel.keywordGroupSearchFieldProperty());
         keywordGroupCaseSensitive.selectedProperty().bindBidirectional(viewModel.keywordGroupCaseSensitiveProperty());
-        keywordGroupRegExp.selectedProperty().bindBidirectional(viewModel.keywordGroupRegExpProperty());
+        keywordGroupRegex.selectedProperty().bindBidirectional(viewModel.keywordGroupRegexProperty());
 
-        searchGroupSearchExpression.textProperty().bindBidirectional(viewModel.searchGroupSearchExpressionProperty());
+        searchGroupSearchTerm.textProperty().bindBidirectional(viewModel.searchGroupSearchTermProperty());
         searchGroupCaseSensitive.selectedProperty().bindBidirectional(viewModel.searchGroupCaseSensitiveProperty());
-        searchGroupRegExp.selectedProperty().bindBidirectional(viewModel.searchGroupRegExpProperty());
+        searchGroupRegex.selectedProperty().bindBidirectional(viewModel.searchGroupRegexProperty());
 
         autoGroupKeywordsOption.selectedProperty().bindBidirectional(viewModel.autoGroupKeywordsOptionProperty());
         autoGroupKeywordsField.textProperty().bindBidirectional(viewModel.autoGroupKeywordsFieldProperty());
@@ -132,11 +180,32 @@ public void initialize() {
         validationVisualizer.setDecoration(new IconValidationDecorator());
         Platform.runLater(() -> {
             validationVisualizer.initVisualization(viewModel.nameValidationStatus(), nameField);
+            validationVisualizer.initVisualization(viewModel.nameContainsDelimiterValidationStatus(), nameField, false);
             validationVisualizer.initVisualization(viewModel.sameNameValidationStatus(), nameField);
-            validationVisualizer.initVisualization(viewModel.searchRegexValidationStatus(), searchGroupSearchExpression);
-            validationVisualizer.initVisualization(viewModel.keywordRegexValidationStatus(), keyWordGroupSearchTerm);
+            validationVisualizer.initVisualization(viewModel.searchRegexValidationStatus(), searchGroupSearchTerm);
+            validationVisualizer.initVisualization(viewModel.searchSearchTermEmptyValidationStatus(), searchGroupSearchTerm);
+            validationVisualizer.initVisualization(viewModel.keywordRegexValidationStatus(), keywordGroupSearchTerm);
+            validationVisualizer.initVisualization(viewModel.keywordSearchTermEmptyValidationStatus(), keywordGroupSearchTerm);
         });
 
+        // ToDo: This comes straight from hell
+
+        nameField.textProperty().addListener((obs, oldval, newval) -> updateComponents());
+        keywordGroupSearchTerm.textProperty().addListener((obs, oldval, newval) -> updateComponents());
+        searchGroupSearchTerm.textProperty().addListener((obs, oldval, newval) -> updateComponents());
+
+        nameField.addEventHandler(KeyEvent.KEY_RELEASED, e -> updateComponents());
+        descriptionField.addEventHandler(KeyEvent.KEY_RELEASED, e -> updateComponents());
+        iconField.addEventHandler(KeyEvent.KEY_RELEASED, e -> updateComponents());
+        keywordGroupSearchField.addEventHandler(KeyEvent.KEY_RELEASED, e -> updateComponents());
+        keywordGroupSearchTerm.addEventHandler(KeyEvent.KEY_RELEASED, e -> updateComponents());
+        keywordGroupCaseSensitive.addEventHandler(ActionEvent.ANY, e -> updateComponents());
+        keywordGroupRegex.addEventHandler(ActionEvent.ANY, e -> updateComponents());
+        searchGroupSearchTerm.addEventHandler(ActionEvent.ANY, e -> updateComponents());
+        searchGroupCaseSensitive.addEventHandler(ActionEvent.ANY, e -> updateComponents());
+        searchGroupRegex.addEventHandler(ActionEvent.ANY, e -> updateComponents());
+
+        // NPE
         // getDialogPane().lookupButton(ButtonType.OK).disableProperty().bind(viewModel.validationStatus().validProperty().not());
     }
 
@@ -145,4 +214,135 @@ private void texGroupBrowse() {
         viewModel.texGroupBrowse();
     }
 
+    // ToDo: The following lines NEED to be changed!
+
+    private void updateComponents() {
+        if (!showHints) {
+            return;
+        }
+
+        String searchField;
+        String searchTerm;
+        if (keywordsRadioButton.isSelected()) {
+            searchField = keywordGroupSearchField.getText().trim();
+            searchTerm = keywordGroupSearchTerm.getText().trim();
+            if (searchField.matches("\\w+") && !searchTerm.isEmpty()) {
+                if (keywordGroupRegex.isSelected()) {
+                    try {
+                        Pattern.compile(searchTerm);
+                        setDescription(GroupDescriptions.getDescriptionForPreview(searchField, searchTerm, keywordGroupCaseSensitive.isSelected(),
+                                keywordGroupRegex.isSelected()));
+                    } catch (PatternSyntaxException e) {
+                        setDescription(formatRegexException(searchTerm, e));
+                    }
+                } else {
+                    setDescription(GroupDescriptions.getDescriptionForPreview(searchField, searchTerm, keywordGroupCaseSensitive.isSelected(),
+                            keywordGroupRegex.isSelected()));
+                }
+            } else {
+                setDescription(Localization.lang(
+                        "Please enter the field to search (e.g. <b>keywords</b>) and the keyword to search it for (e.g. <b>electrical</b>)."));
+            }
+        } else if (searchRadioButton.isSelected()) {
+            searchTerm = searchGroupSearchTerm.getText().trim();
+            if (!searchTerm.isEmpty()) {
+                setDescription(fromTextFlowToHTMLString(SearchDescribers
+                        .getSearchDescriberFor(new SearchQuery(
+                                searchTerm,
+                                searchGroupCaseSensitive.isSelected(),
+                                searchGroupRegex.isSelected()))
+                        .getDescription()));
+                if (searchGroupRegex.isSelected()) {
+                    try {
+                        Pattern.compile(searchTerm);
+                    } catch (PatternSyntaxException e) {
+                        setDescription(formatRegexException(searchTerm, e));
+                    }
+                }
+            } else {
+                setDescription(Localization
+                        .lang("Please enter a search term. For example, to search all fields for <b>Smith</b>, enter:<p>"
+                                + "<tt>smith</tt><p>"
+                                + "To search the field <b>Author</b> for <b>Smith</b> and the field <b>Title</b> for <b>electrical</b>, enter:<p>"
+                                + "<tt>author=smith and title=electrical</tt>"));
+            }
+        } else if (explicitRadioButton.isSelected()) {
+            setDescription(GroupDescriptions.getDescriptionForPreview());
+        }
+    }
+
+    private void setDescription(String description) {
+        hintTextFlow.getChildren().setAll(createFormattedDescription(description));
+    }
+
+    private ArrayList<Node> createFormattedDescription(String descriptionHTML) {
+        ArrayList<Node> nodes = new ArrayList<>();
+
+        descriptionHTML = descriptionHTML.replaceAll("<p>|<br>", "\n");
+
+        String[] boldSplit = descriptionHTML.split("(?=<b>)|(?<=</b>)|(?=<i>)|(?<=</i>)|(?=<tt>)|(?<=</tt>)|(?=<kbd>)|(?<=</kbd>)");
+
+        for (String bs : boldSplit) {
+
+            if (bs.matches("<b>[^<>]*</b>")) {
+
+                bs = bs.replaceAll("<b>|</b>", "");
+                Text textElement = new Text(bs);
+                textElement.setStyle("-fx-font-weight: bold");
+                nodes.add(textElement);
+            } else if (bs.matches("<i>[^<>]*</i>")) {
+
+                bs = bs.replaceAll("<i>|</i>", "");
+                Text textElement = new Text(bs);
+                textElement.setStyle("-fx-font-style: italic");
+                nodes.add(textElement);
+            } else if (bs.matches("<tt>[^<>]*</tt>|<kbd>[^<>]*</kbd>")) {
+
+                bs = bs.replaceAll("<tt>|</tt>|<kbd>|</kbd>", "");
+                Text textElement = new Text(bs);
+                textElement.setStyle("-fx-font-family: 'Courier New', Courier, monospace");
+                nodes.add(textElement);
+            } else {
+                nodes.add(new Text(bs));
+            }
+        }
+
+        return nodes;
+    }
+
+    private static String formatRegexException(String regExp, Exception e) {
+        String[] sa = e.getMessage().split("\\n");
+        StringBuilder sb = new StringBuilder();
+        for (int i = 0; i < sa.length; ++i) {
+            if (i > 0) {
+                sb.append("<br>");
+            }
+            sb.append(StringUtil.quoteForHTML(sa[i]));
+        }
+        String s = Localization.lang(
+                "The regular expression <b>%0</b> is invalid:",
+                StringUtil.quoteForHTML(regExp))
+                + "<p><tt>"
+                + sb
+                + "</tt>";
+        if (!(e instanceof PatternSyntaxException)) {
+            return s;
+        }
+        int lastNewline = s.lastIndexOf("<br>");
+        int hat = s.lastIndexOf('^');
+        if ((lastNewline >= 0) && (hat >= 0) && (hat > lastNewline)) {
+            return s.substring(0, lastNewline + 4) + s.substring(lastNewline + 4).replace(" ", "&nbsp;");
+        }
+        return s;
+    }
+
+    private String fromTextFlowToHTMLString(TextFlow textFlow) {
+        StringBuilder htmlStringBuilder = new StringBuilder();
+        for (Node node : textFlow.getChildren()) {
+            if (node instanceof Text) {
+                htmlStringBuilder.append(TooltipTextUtil.textToHTMLString((Text) node));
+            }
+        }
+        return htmlStringBuilder.toString();
+    }
 }
diff --git a/src/main/java/org/jabref/gui/groups/GroupDialogViewModel.java b/src/main/java/org/jabref/gui/groups/GroupDialogViewModel.java
index 10096b70311..2034d81a05c 100644
--- a/src/main/java/org/jabref/gui/groups/GroupDialogViewModel.java
+++ b/src/main/java/org/jabref/gui/groups/GroupDialogViewModel.java
@@ -10,11 +10,14 @@
 import java.util.regex.PatternSyntaxException;
 
 import javafx.beans.property.BooleanProperty;
+import javafx.beans.property.ListProperty;
 import javafx.beans.property.ObjectProperty;
 import javafx.beans.property.SimpleBooleanProperty;
+import javafx.beans.property.SimpleListProperty;
 import javafx.beans.property.SimpleObjectProperty;
 import javafx.beans.property.SimpleStringProperty;
 import javafx.beans.property.StringProperty;
+import javafx.collections.FXCollections;
 import javafx.scene.control.ButtonType;
 import javafx.scene.paint.Color;
 
@@ -57,11 +60,8 @@ public class GroupDialogViewModel {
     private final StringProperty descriptionProperty = new SimpleStringProperty("");
     private final StringProperty iconProperty = new SimpleStringProperty("");
     private final ObjectProperty<Color> colorProperty = new SimpleObjectProperty<>();
-
-    // Hierarchical Context
-    private final BooleanProperty hierarchyIndependentProperty = new SimpleBooleanProperty();
-    private final BooleanProperty hierarchyIntersectionProperty = new SimpleBooleanProperty();
-    private final BooleanProperty hierarchyUnionProperty = new SimpleBooleanProperty();
+    private final ListProperty<GroupHierarchyType> groupHierarchyListProperty = new SimpleListProperty<>();
+    private final ObjectProperty<GroupHierarchyType> groupHierarchySelectedProperty = new SimpleObjectProperty<>();
 
     // Type
     private final BooleanProperty typeExplicitProperty = new SimpleBooleanProperty();
@@ -74,11 +74,11 @@ public class GroupDialogViewModel {
     private final StringProperty keywordGroupSearchTermProperty = new SimpleStringProperty("");
     private final StringProperty keywordGroupSearchFieldProperty = new SimpleStringProperty("");
     private final BooleanProperty keywordGroupCaseSensitiveProperty = new SimpleBooleanProperty();
-    private final BooleanProperty keywordGroupRegExpProperty = new SimpleBooleanProperty();
+    private final BooleanProperty keywordGroupRegexProperty = new SimpleBooleanProperty();
 
-    private final StringProperty searchGroupSearchExpressionProperty = new SimpleStringProperty("");
+    private final StringProperty searchGroupSearchTermProperty = new SimpleStringProperty("");
     private final BooleanProperty searchGroupCaseSensitiveProperty = new SimpleBooleanProperty();
-    private final BooleanProperty searchGroupRegExpProperty = new SimpleBooleanProperty();
+    private final BooleanProperty searchGroupRegexProperty = new SimpleBooleanProperty();
 
     private final BooleanProperty autoGroupKeywordsOptionProperty = new SimpleBooleanProperty();
     private final StringProperty autoGroupKeywordsFieldProperty = new SimpleStringProperty("");
@@ -92,27 +92,49 @@ public class GroupDialogViewModel {
     // Description text
     private final StringProperty hintTextProperty = new SimpleStringProperty("");
 
-    private final Validator nameValidator;
-    private final Validator sameNameValidator;
-    private final Validator keywordRegexValidator;
-    private final Validator searchRegexValidator;
+    private Validator nameValidator;
+    private Validator nameContainsDelimiterValidator;
+    private Validator sameNameValidator;
+    private Validator keywordRegexValidator;
+    private Validator keywordSearchTermEmptyValidator;
+    private Validator searchRegexValidator;
+    private Validator searchSearchTermEmptyValidator;
+    private CompositeValidator validator;
 
     private final DialogService dialogService;
     private final JabRefPreferences preferences;
     private final BasePanel basePanel;
     private final AbstractGroup editedGroup;
 
+    private final Character keywordDelimiter;
+
     public GroupDialogViewModel(DialogService dialogService, BasePanel basePanel, JabRefPreferences preferences, AbstractGroup editedGroup) {
         this.dialogService = dialogService;
         this.preferences = preferences;
         this.basePanel = basePanel;
         this.editedGroup = editedGroup;
 
+        this.keywordDelimiter = Globals.prefs.getKeywordDelimiter();
+
+        setupValidation();
+        setValues();
+    }
+
+    private void setupValidation() {
         nameValidator = new FunctionBasedValidator<>(
                 nameProperty,
                 StringUtil::isNotBlank,
                 ValidationMessage.error(Localization.lang("Please enter a name for the group.")));
 
+        nameContainsDelimiterValidator = new FunctionBasedValidator<>(
+                nameProperty,
+                name -> !name.contains(Character.toString(keywordDelimiter)),
+                ValidationMessage.warning(
+                        Localization.lang(
+                                "The group name contains the keyword separator \"%0\" and thus probably does not work as expected.",
+                                Character.toString(keywordDelimiter)
+                        )));
+
         sameNameValidator = new FunctionBasedValidator<>(
                 nameProperty,
                 name -> {
@@ -136,7 +158,7 @@ public GroupDialogViewModel(DialogService dialogService, BasePanel basePanel, Ja
         keywordRegexValidator = new FunctionBasedValidator<>(
                 keywordGroupSearchTermProperty,
                 input -> {
-                    if (!keywordGroupRegExpProperty.getValue()) {
+                    if (!keywordGroupRegexProperty.getValue()) {
                         return true;
                     }
 
@@ -152,15 +174,24 @@ public GroupDialogViewModel(DialogService dialogService, BasePanel basePanel, Ja
                     }
                 },
                 ValidationMessage.error(String.format("%s > %n %s %n %n %s %n %s",
-                        Localization.lang("Dynamically group entries by searching a field for a keyword"),
+                        Localization.lang("Searching for keywords"),
                         Localization.lang("Keywords"),
                         Localization.lang("Invalid regular expression:"),
                         keywordGroupSearchTermProperty.getValue())));
 
+        keywordSearchTermEmptyValidator = new FunctionBasedValidator<>(
+                keywordGroupSearchTermProperty,
+                input -> !StringUtil.isNullOrEmpty(input),
+                ValidationMessage.error(String.format("%s > %n %s %n %n %s",
+                        Localization.lang("Searching for keywords"),
+                        Localization.lang("Keywords"),
+                        Localization.lang("Search term is empty.")
+                )));
+
         searchRegexValidator = new FunctionBasedValidator<>(
-                searchGroupSearchExpressionProperty,
+                searchGroupSearchTermProperty,
                 input -> {
-                    if (!searchGroupRegExpProperty.getValue()) {
+                    if (!searchGroupRegexProperty.getValue()) {
                         return true;
                     }
 
@@ -175,90 +206,97 @@ public GroupDialogViewModel(DialogService dialogService, BasePanel basePanel, Ja
                         return false;
                     }
                 },
-                ValidationMessage.error(String.format("%s > %n %s %n %n %s %n %s",
-                        Localization.lang("Dynamically group entries by a free-form search expression"),
-                        Localization.lang("Keywords"),
+                ValidationMessage.error(String.format("%s > %n %s %n %s",
+                        Localization.lang("Free search expression"),
                         Localization.lang("Invalid regular expression:"),
-                        searchGroupSearchExpressionProperty.getValue())));
+                        searchGroupSearchTermProperty.getValue())));
+
+        searchSearchTermEmptyValidator = new FunctionBasedValidator<>(
+                searchGroupSearchTermProperty,
+                input -> !StringUtil.isNullOrEmpty(input),
+                ValidationMessage.error(String.format("%s > %n %s",
+                        Localization.lang("Free search expression"),
+                        Localization.lang("Search term is empty.")
+                )));
+
+        validator = new CompositeValidator(nameValidator,sameNameValidator);
+
+        typeSearchProperty.addListener((obs,oldVal,newVal) -> {
+            if (newVal) {
+                validator.addValidators(searchRegexValidator, searchSearchTermEmptyValidator);
+            } else {
+                validator.removeValidators(searchRegexValidator, searchSearchTermEmptyValidator);
+            }
+        });
 
-        setValues();
+        typeKeywordsProperty.addListener((obs,oldVal,newVal) -> {
+            if (newVal) {
+                validator.addValidators(keywordRegexValidator, keywordSearchTermEmptyValidator);
+            } else {
+                validator.removeValidators(keywordRegexValidator, keywordSearchTermEmptyValidator);
+            }
+        });
     }
 
     public AbstractGroup resultConverter(ButtonType button) {
         if (button == ButtonType.OK) {
+            ValidationStatus validationStatus = validator.getValidationStatus();
+            if (validationStatus.getHighestMessage().isPresent()) {
+                dialogService.showErrorDialogAndWait(validationStatus.getHighestMessage().get().getMessage());
+                return null;
+            }
+
             AbstractGroup resultingGroup = null;
             try {
                 String groupName = nameProperty.getValue().trim();
                 if (typeExplicitProperty.getValue()) {
-                    Character keywordDelimiter = Globals.prefs.getKeywordDelimiter();
-                    if (groupName.contains(Character.toString(keywordDelimiter))) {
-                        dialogService.showWarningDialogAndWait(null, Localization.lang("The group name contains the keyword separator \"%0\" and thus probably does not work as expected.", Character.toString(keywordDelimiter)));
-                    }
-
-                    Optional<GroupTreeNode> rootGroup = basePanel.getBibDatabaseContext().getMetaData().getGroups();
-                    if (rootGroup.isPresent()) {
-                        int groupsWithSameName = rootGroup.get().findChildrenSatisfying(group -> group.getName().equals(groupName)).size();
-                        boolean warnAboutSameName = false;
-                        if ((editedGroup == null) && (groupsWithSameName > 0)) {
-                            // New group but there is already one group with the same name
-                            warnAboutSameName = true;
-                        }
-                        if ((editedGroup != null) && !editedGroup.getName().equals(groupName) && (groupsWithSameName > 0)) {
-                            // Edit group, changed name to something that is already present
-                            warnAboutSameName = true;
-                        }
-
-                        if (warnAboutSameName) {
-                            dialogService.showErrorDialogAndWait(Localization.lang("There exists already a group with the same name.", Character.toString(keywordDelimiter)));
-                            return null;
-                        }
-                    }
-
-                    resultingGroup = new ExplicitGroup(groupName, getContext(),
+                    resultingGroup = new ExplicitGroup(
+                            groupName,
+                            groupHierarchySelectedProperty.getValue(),
                             keywordDelimiter);
                 } else if (typeKeywordsProperty.getValue()) {
-                    if (keywordGroupRegExpProperty.getValue()) {
+                    if (keywordGroupRegexProperty.getValue()) {
                         resultingGroup = new RegexKeywordGroup(
                                 groupName,
-                                getContext(),
+                                groupHierarchySelectedProperty.getValue(),
                                 FieldFactory.parseField(keywordGroupSearchFieldProperty.getValue().trim()),
                                 keywordGroupSearchTermProperty.getValue().trim(),
                                 keywordGroupCaseSensitiveProperty.getValue());
                     } else {
                         resultingGroup = new WordKeywordGroup(
                                 groupName,
-                                getContext(),
+                                groupHierarchySelectedProperty.getValue(),
                                 FieldFactory.parseField(keywordGroupSearchFieldProperty.getValue().trim()),
                                 keywordGroupSearchTermProperty.getValue().trim(),
                                 keywordGroupCaseSensitiveProperty.getValue(),
-                                Globals.prefs.getKeywordDelimiter(),
+                                keywordDelimiter,
                                 false);
                     }
                 } else if (typeSearchProperty.getValue()) {
                     resultingGroup = new SearchGroup(
                             groupName,
-                            getContext(),
-                            searchGroupSearchExpressionProperty.getValue().trim(),
+                            groupHierarchySelectedProperty.getValue(),
+                            searchGroupSearchTermProperty.getValue().trim(),
                             searchGroupCaseSensitiveProperty.getValue(),
-                            searchGroupRegExpProperty.getValue());
+                            searchGroupRegexProperty.getValue());
                 } else if (typeAutoProperty.getValue()) {
                     if (autoGroupKeywordsOptionProperty.getValue()) {
                         resultingGroup = new AutomaticKeywordGroup(
                                 groupName,
-                                getContext(),
+                                groupHierarchySelectedProperty.getValue(),
                                 FieldFactory.parseField(autoGroupKeywordsFieldProperty.getValue().trim()),
                                 autoGroupKeywordsDelimiterProperty.getValue().charAt(0),
                                 autoGroupKeywordsHierarchicalDelimiterProperty.getValue().charAt(0));
                     } else {
                         resultingGroup = new AutomaticPersonsGroup(
                                 groupName,
-                                getContext(),
+                                groupHierarchySelectedProperty.getValue(),
                                 FieldFactory.parseField(autoGroupPersonsFieldProperty.getValue().trim()));
                     }
                 } else if (typeTexProperty.getValue()) {
                     resultingGroup = TexGroup.create(
                             groupName,
-                            getContext(),
+                            groupHierarchySelectedProperty.getValue(),
                             Paths.get(texGroupFilePathProperty.getValue().trim()),
                             new DefaultAuxParser(new BibDatabase()),
                             Globals.getFileUpdateMonitor(),
@@ -283,24 +321,26 @@ public AbstractGroup resultConverter(ButtonType button) {
     }
 
     public void setValues() {
+        groupHierarchyListProperty.setValue(FXCollections.observableArrayList(GroupHierarchyType.values()));
+
         if (editedGroup == null) {
             // creating new group -> defaults!
             colorProperty.setValue(IconTheme.getDefaultGroupColor());
             typeExplicitProperty.setValue(true);
-            setContext(GroupHierarchyType.INDEPENDENT);
+            groupHierarchySelectedProperty.setValue(GroupHierarchyType.INDEPENDENT);
         } else {
             nameProperty.setValue(editedGroup.getName());
             colorProperty.setValue(editedGroup.getColor().orElse(IconTheme.getDefaultGroupColor()));
             descriptionProperty.setValue(editedGroup.getDescription().orElse(""));
             iconProperty.setValue(editedGroup.getIconName().orElse(""));
-            setContext(editedGroup.getHierarchicalContext());
+            groupHierarchySelectedProperty.setValue(editedGroup.getHierarchicalContext());
 
             if (editedGroup.getClass() == WordKeywordGroup.class) {
                 WordKeywordGroup group = (WordKeywordGroup) editedGroup;
                 keywordGroupSearchFieldProperty.setValue(group.getSearchField().getName());
                 keywordGroupSearchTermProperty.setValue(group.getSearchExpression());
                 keywordGroupCaseSensitiveProperty.setValue(group.isCaseSensitive());
-                keywordGroupRegExpProperty.setValue(false);
+                keywordGroupRegexProperty.setValue(false);
 
                 typeExplicitProperty.setValue(false);
                 typeKeywordsProperty.setValue(true);
@@ -312,7 +352,7 @@ public void setValues() {
                 keywordGroupSearchFieldProperty.setValue(group.getSearchField().getName());
                 keywordGroupSearchTermProperty.setValue(group.getSearchExpression());
                 keywordGroupCaseSensitiveProperty.setValue(group.isCaseSensitive());
-                keywordGroupRegExpProperty.setValue(true);
+                keywordGroupRegexProperty.setValue(true);
 
                 typeExplicitProperty.setValue(false);
                 typeKeywordsProperty.setValue(true);
@@ -321,9 +361,9 @@ public void setValues() {
                 typeTexProperty.setValue(false);
             } else if (editedGroup.getClass() == SearchGroup.class) {
                 SearchGroup group = (SearchGroup) editedGroup;
-                searchGroupSearchExpressionProperty.setValue(group.getSearchExpression());
+                searchGroupSearchTermProperty.setValue(group.getSearchExpression());
                 searchGroupCaseSensitiveProperty.setValue(group.isCaseSensitive());
-                searchGroupRegExpProperty.setValue(group.isRegularExpression());
+                searchGroupRegexProperty.setValue(group.isRegularExpression());
 
                 typeExplicitProperty.setValue(false);
                 typeKeywordsProperty.setValue(false);
@@ -369,12 +409,10 @@ public void texGroupBrowse() {
                 .addExtensionFilter(StandardFileType.AUX)
                 .withDefaultExtension(StandardFileType.AUX)
                 .withInitialDirectory(Globals.prefs.get(JabRefPreferences.WORKING_DIRECTORY)).build();
-        dialogService.showFileOpenDialog(fileDialogConfiguration).ifPresent(file -> texGroupFilePathProperty.setValue(relativise(file.toAbsolutePath()).toString()));
-    }
-
-    private Path relativise(Path path) {
-        List<Path> fileDirectories = getFileDirectoriesAsPaths();
-        return FileUtil.relativize(path, fileDirectories);
+        dialogService.showFileOpenDialog(fileDialogConfiguration)
+                     .ifPresent(file -> texGroupFilePathProperty.setValue(
+                             FileUtil.relativize(file.toAbsolutePath(), getFileDirectoriesAsPaths()).toString()
+                     ));
     }
 
     private List<Path> getFileDirectoriesAsPaths() {
@@ -385,57 +423,21 @@ private List<Path> getFileDirectoriesAsPaths() {
         return fileDirs;
     }
 
-    public ValidationStatus validationStatus() {
-        CompositeValidator validator = new CompositeValidator();
-
-        validator.addValidators(nameValidator);
-        validator.addValidators(sameNameValidator);
-
-        if (typeSearchProperty.getValue()) {
-            validator.addValidators(searchRegexValidator);
-        }
-
-        if (typeKeywordsProperty.getValue()) {
-            validator.addValidators(keywordRegexValidator);
-        }
-
-        return validator.getValidationStatus();
-    }
+    public ValidationStatus validationStatus() { return validator.getValidationStatus(); }
 
     public ValidationStatus nameValidationStatus() { return nameValidator.getValidationStatus(); }
 
+    public ValidationStatus nameContainsDelimiterValidationStatus() { return nameContainsDelimiterValidator.getValidationStatus(); }
+
     public ValidationStatus sameNameValidationStatus() { return sameNameValidator.getValidationStatus(); }
 
     public ValidationStatus searchRegexValidationStatus() { return searchRegexValidator.getValidationStatus(); }
 
-    public ValidationStatus keywordRegexValidationStatus() { return keywordRegexValidator.getValidationStatus(); }
+    public ValidationStatus searchSearchTermEmptyValidationStatus() { return searchSearchTermEmptyValidator.getValidationStatus(); }
 
-    private GroupHierarchyType getContext() {
-        if (hierarchyIndependentProperty.getValue()) {
-            return GroupHierarchyType.INDEPENDENT;
-        }
-        if (hierarchyIntersectionProperty.getValue()) {
-            return GroupHierarchyType.REFINING;
-        }
-        if (hierarchyUnionProperty.getValue()) {
-            return GroupHierarchyType.INCLUDING;
-        }
-        return GroupHierarchyType.INDEPENDENT; // default
-    }
+    public ValidationStatus keywordRegexValidationStatus() { return keywordRegexValidator.getValidationStatus(); }
 
-    private void setContext(GroupHierarchyType context) {
-        switch (context) {
-            case INDEPENDENT:
-                hierarchyIndependentProperty.setValue(true);
-                break;
-            case REFINING:
-                hierarchyIntersectionProperty.setValue(true);
-                break;
-            case INCLUDING:
-                hierarchyUnionProperty.setValue(true);
-                break;
-        }
-    }
+    public ValidationStatus keywordSearchTermEmptyValidationStatus() { return keywordSearchTermEmptyValidator.getValidationStatus(); }
 
     public StringProperty nameProperty() { return nameProperty; }
 
@@ -445,11 +447,9 @@ private void setContext(GroupHierarchyType context) {
 
     public ObjectProperty<Color> colorFieldProperty() { return colorProperty; }
 
-    public BooleanProperty hierarchyIndependentProperty() { return hierarchyIndependentProperty; }
-
-    public BooleanProperty hierarchyIntersectionProperty() { return hierarchyIntersectionProperty; }
+    public ListProperty<GroupHierarchyType> groupHierarchyListProperty() { return groupHierarchyListProperty; }
 
-    public BooleanProperty hierarchyUnionProperty() { return hierarchyUnionProperty; }
+    public ObjectProperty<GroupHierarchyType> groupHierarchySelectedProperty() { return groupHierarchySelectedProperty; }
 
     public BooleanProperty typeExplicitProperty() { return typeExplicitProperty; }
 
@@ -467,13 +467,13 @@ private void setContext(GroupHierarchyType context) {
 
     public BooleanProperty keywordGroupCaseSensitiveProperty() { return keywordGroupCaseSensitiveProperty; }
 
-    public BooleanProperty keywordGroupRegExpProperty() { return keywordGroupRegExpProperty; }
+    public BooleanProperty keywordGroupRegexProperty() { return keywordGroupRegexProperty; }
 
-    public StringProperty searchGroupSearchExpressionProperty() { return searchGroupSearchExpressionProperty; }
+    public StringProperty searchGroupSearchTermProperty() { return searchGroupSearchTermProperty; }
 
     public BooleanProperty searchGroupCaseSensitiveProperty() { return searchGroupCaseSensitiveProperty; }
 
-    public BooleanProperty searchGroupRegExpProperty() { return searchGroupRegExpProperty; }
+    public BooleanProperty searchGroupRegexProperty() { return searchGroupRegexProperty; }
 
     public BooleanProperty autoGroupKeywordsOptionProperty() { return autoGroupKeywordsOptionProperty; }
 
diff --git a/src/main/resources/l10n/JabRef_en.properties b/src/main/resources/l10n/JabRef_en.properties
index ccc385c0d6b..5bc54e829de 100644
--- a/src/main/resources/l10n/JabRef_en.properties
+++ b/src/main/resources/l10n/JabRef_en.properties
@@ -1221,7 +1221,7 @@ Not\ connected\ to\ any\ Writer\ document.\ Please\ make\ sure\ a\ document\ is\
 Removed\ all\ subgroups\ of\ group\ "%0".=Removed all subgroups of group "%0".
 To\ disable\ the\ memory\ stick\ mode\ rename\ or\ remove\ the\ jabref.xml\ file\ in\ the\ same\ folder\ as\ JabRef.=To disable the memory stick mode rename or remove the jabref.xml file in the same folder as JabRef.
 Unable\ to\ connect.\ One\ possible\ reason\ is\ that\ JabRef\ and\ OpenOffice/LibreOffice\ are\ not\ both\ running\ in\ either\ 32\ bit\ mode\ or\ 64\ bit\ mode.=Unable to connect. One possible reason is that JabRef and OpenOffice/LibreOffice are not both running in either 32 bit mode or 64 bit mode.
-Use\ the\ following\ delimiter\ character(s)\:=Use the following delimiter character(s):
+Delimiter\ character(s)\:=Delimiter character(s):
 When\ downloading\ files,\ or\ moving\ linked\ files\ to\ the\ file\ directory,\ prefer\ the\ BIB\ file\ location\ rather\ than\ the\ file\ directory\ set\ above=When downloading files, or moving linked files to the file directory, prefer the BIB file location rather than the file directory set above
 Your\ style\ file\ specifies\ the\ character\ format\ '%0',\ which\ is\ undefined\ in\ your\ current\ OpenOffice/LibreOffice\ document.=Your style file specifies the character format '%0', which is undefined in your current OpenOffice/LibreOffice document.
 Your\ style\ file\ specifies\ the\ paragraph\ format\ '%0',\ which\ is\ undefined\ in\ your\ current\ OpenOffice/LibreOffice\ document.=Your style file specifies the paragraph format '%0', which is undefined in your current OpenOffice/LibreOffice document.
@@ -2103,3 +2103,14 @@ Mark\ all\ changes\ as\ accepted=Mark all changes as accepted
 Unmark\ all\ changes=Unmark all changes
 
 Invalid\ regular\ expression\:=Invalid regular expression:
+
+Independent=Independent
+Intersection=Intersection
+Union=Union
+Collect\ by=Collect by
+Explicit\ selection=Explicit selection
+Searching\ for\ keywords=Searching for keywords
+Free\ search\ expression=Free search expression
+Specified\ keywords=Specified keywords
+Cited\ entries=Cited entries
+Search\ term\ is\ empty.=Search term is empty.

From c77cd42d27b7793dc5f030b0bdedaab88812de66 Mon Sep 17 00:00:00 2001
From: Carl Christian Snethlage <cc.snethlage@gmail.com>
Date: Sun, 12 Jan 2020 17:45:47 +0100
Subject: [PATCH 3/9] Moved GroupDescription-stuff to proper class

---
 src/main/java/module-info.java                |  1 +
 .../jabref/gui/groups/GroupDescriptions.java  | 79 +++++++++++++++++
 .../org/jabref/gui/groups/GroupDialog.fxml    |  7 +-
 .../org/jabref/gui/groups/GroupDialog.java    | 82 +-----------------
 .../jabref/gui/groups/GroupDialogView.java    | 84 +------------------
 5 files changed, 91 insertions(+), 162 deletions(-)

diff --git a/src/main/java/module-info.java b/src/main/java/module-info.java
index 38158c02c12..62d717eb4cf 100644
--- a/src/main/java/module-info.java
+++ b/src/main/java/module-info.java
@@ -69,4 +69,5 @@
     requires commons.csv;
     requires io.github.javadiffutils;
     requires flowless;
+    requires ojdbc10;
 }
diff --git a/src/main/java/org/jabref/gui/groups/GroupDescriptions.java b/src/main/java/org/jabref/gui/groups/GroupDescriptions.java
index 6548c0cb1a8..bfa28218171 100644
--- a/src/main/java/org/jabref/gui/groups/GroupDescriptions.java
+++ b/src/main/java/org/jabref/gui/groups/GroupDescriptions.java
@@ -1,5 +1,13 @@
 package org.jabref.gui.groups;
 
+import java.util.ArrayList;
+import java.util.regex.PatternSyntaxException;
+
+import javafx.scene.Node;
+import javafx.scene.text.Text;
+import javafx.scene.text.TextFlow;
+
+import org.jabref.gui.util.TooltipTextUtil;
 import org.jabref.logic.l10n.Localization;
 import org.jabref.model.groups.ExplicitGroup;
 import org.jabref.model.groups.KeywordGroup;
@@ -119,4 +127,75 @@ public static String getShortDescription(SearchGroup searchGroup, boolean showDy
         return sb.toString();
     }
 
+    protected static String fromTextFlowToHTMLString(TextFlow textFlow) {
+        StringBuilder htmlStringBuilder = new StringBuilder();
+        for (Node node : textFlow.getChildren()) {
+            if (node instanceof Text) {
+                htmlStringBuilder.append(TooltipTextUtil.textToHTMLString((Text) node));
+            }
+        }
+        return htmlStringBuilder.toString();
+    }
+
+    protected static String formatRegexException(String regExp, Exception e) {
+        String[] sa = e.getMessage().split("\\n");
+        StringBuilder sb = new StringBuilder();
+        for (int i = 0; i < sa.length; ++i) {
+            if (i > 0) {
+                sb.append("<br>");
+            }
+            sb.append(StringUtil.quoteForHTML(sa[i]));
+        }
+        String s = Localization.lang(
+                "The regular expression <b>%0</b> is invalid:",
+                StringUtil.quoteForHTML(regExp))
+                + "<p><tt>"
+                + sb
+                + "</tt>";
+        if (!(e instanceof PatternSyntaxException)) {
+            return s;
+        }
+        int lastNewline = s.lastIndexOf("<br>");
+        int hat = s.lastIndexOf('^');
+        if ((lastNewline >= 0) && (hat >= 0) && (hat > lastNewline)) {
+            return s.substring(0, lastNewline + 4) + s.substring(lastNewline + 4).replace(" ", "&nbsp;");
+        }
+        return s;
+    }
+
+    protected static ArrayList<Node> createFormattedDescription(String descriptionHTML) {
+        ArrayList<Node> nodes = new ArrayList<>();
+
+        descriptionHTML = descriptionHTML.replaceAll("<p>|<br>", "\n");
+
+        String[] boldSplit = descriptionHTML.split("(?=<b>)|(?<=</b>)|(?=<i>)|(?<=</i>)|(?=<tt>)|(?<=</tt>)|(?=<kbd>)|(?<=</kbd>)");
+
+        for (String bs : boldSplit) {
+
+            if (bs.matches("<b>[^<>]*</b>")) {
+
+                bs = bs.replaceAll("<b>|</b>", "");
+                Text textElement = new Text(bs);
+                textElement.setStyle("-fx-font-weight: bold");
+                nodes.add(textElement);
+            } else if (bs.matches("<i>[^<>]*</i>")) {
+
+                bs = bs.replaceAll("<i>|</i>", "");
+                Text textElement = new Text(bs);
+                textElement.setStyle("-fx-font-style: italic");
+                nodes.add(textElement);
+            } else if (bs.matches("<tt>[^<>]*</tt>|<kbd>[^<>]*</kbd>")) {
+
+                bs = bs.replaceAll("<tt>|</tt>|<kbd>|</kbd>", "");
+                Text textElement = new Text(bs);
+                textElement.setStyle("-fx-font-family: 'Courier New', Courier, monospace");
+                nodes.add(textElement);
+            } else {
+                nodes.add(new Text(bs));
+            }
+        }
+
+        return nodes;
+    }
+
 }
diff --git a/src/main/java/org/jabref/gui/groups/GroupDialog.fxml b/src/main/java/org/jabref/gui/groups/GroupDialog.fxml
index ca74c485979..873dd355aa5 100644
--- a/src/main/java/org/jabref/gui/groups/GroupDialog.fxml
+++ b/src/main/java/org/jabref/gui/groups/GroupDialog.fxml
@@ -1,10 +1,10 @@
 <?xml version="1.0" encoding="UTF-8"?>
 
+<?import javafx.geometry.Insets?>
 <?import javafx.scene.control.*?>
 <?import javafx.scene.layout.*?>
-
-<?import javafx.geometry.Insets?>
 <?import javafx.scene.text.TextFlow?>
+
 <DialogPane prefHeight="300.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/10.0.2-internal"
             xmlns:fx="http://javafx.com/fxml/1" fx:controller="org.jabref.gui.groups.GroupDialogView">
     <content>
@@ -39,9 +39,8 @@
                     <ComboBox fx:id="hierarchicalContextCombo" minWidth="130.0" maxWidth="130.0" prefWidth="130.0"/>
                 </VBox>
             </HBox>
-            <Separator/>
             <HBox spacing="4.0">
-                <VBox spacing="4.0">
+                <VBox spacing="10.0">
                     <Label text="%Collect by"/>
                     <RadioButton fx:id="explicitRadioButton" toggleGroup="$type" wrapText="true"
                                  text="%Explicit selection">
diff --git a/src/main/java/org/jabref/gui/groups/GroupDialog.java b/src/main/java/org/jabref/gui/groups/GroupDialog.java
index 9097cc244b9..79ba208797e 100644
--- a/src/main/java/org/jabref/gui/groups/GroupDialog.java
+++ b/src/main/java/org/jabref/gui/groups/GroupDialog.java
@@ -33,7 +33,6 @@
 import javafx.scene.layout.VBox;
 import javafx.scene.text.Font;
 import javafx.scene.text.FontPosture;
-import javafx.scene.text.Text;
 import javafx.scene.text.TextFlow;
 
 import org.jabref.Globals;
@@ -44,7 +43,6 @@
 import org.jabref.gui.search.rules.describer.SearchDescribers;
 import org.jabref.gui.util.BaseDialog;
 import org.jabref.gui.util.FileDialogConfiguration;
-import org.jabref.gui.util.TooltipTextUtil;
 import org.jabref.logic.auxparser.DefaultAuxParser;
 import org.jabref.logic.l10n.Localization;
 import org.jabref.logic.search.SearchQuery;
@@ -66,7 +64,6 @@
 import org.jabref.model.groups.TexGroup;
 import org.jabref.model.groups.WordKeywordGroup;
 import org.jabref.model.metadata.MetaData;
-import org.jabref.model.strings.StringUtil;
 import org.jabref.preferences.JabRefPreferences;
 
 // import com.jfoenix.controls.JFXColorPicker;
@@ -435,32 +432,6 @@ public GroupDialog(DialogService dialogService, AbstractGroup editedGroup) {
         this(dialogService, JabRefGUI.getMainFrame().getCurrentBasePanel(), Globals.prefs, editedGroup);
     }
 
-    private static String formatRegExException(String regExp, Exception e) {
-        String[] sa = e.getMessage().split("\\n");
-        StringBuilder sb = new StringBuilder();
-        for (int i = 0; i < sa.length; ++i) {
-            if (i > 0) {
-                sb.append("<br>");
-            }
-            sb.append(StringUtil.quoteForHTML(sa[i]));
-        }
-        String s = Localization.lang(
-                "The regular expression <b>%0</b> is invalid:",
-                StringUtil.quoteForHTML(regExp))
-                + "<p><tt>"
-                + sb
-                + "</tt>";
-        if (!(e instanceof PatternSyntaxException)) {
-            return s;
-        }
-        int lastNewline = s.lastIndexOf("<br>");
-        int hat = s.lastIndexOf('^');
-        if ((lastNewline >= 0) && (hat >= 0) && (hat > lastNewline)) {
-            return s.substring(0, lastNewline + 4) + s.substring(lastNewline + 4).replace(" ", "&nbsp;");
-        }
-        return s;
-    }
-
     private VBox createOptionsTexGroup() {
         VBox texPanel = new VBox();
         texPanel.setVisible(false);
@@ -571,7 +542,7 @@ private void updateComponents() {
                                 keywordGroupRegExp.isSelected()));
                     } catch (PatternSyntaxException e) {
                         okEnabled = false;
-                        setDescription(formatRegExException(s2, e));
+                        setDescription(GroupDescriptions.formatRegexException(s2, e));
                     }
                 } else {
                     setDescription(GroupDescriptions.getDescriptionForPreview(s1, s2, keywordGroupCaseSensitive.isSelected(),
@@ -586,7 +557,7 @@ private void updateComponents() {
             s1 = searchGroupSearchExpression.getText().trim();
             okEnabled = okEnabled & !s1.isEmpty();
             if (okEnabled) {
-                setDescription(fromTextFlowToHTMLString(SearchDescribers.getSearchDescriberFor(
+                setDescription(GroupDescriptions.fromTextFlowToHTMLString(SearchDescribers.getSearchDescriberFor(
                         new SearchQuery(s1, isCaseSensitive(), isRegex()))
                                                                         .getDescription()));
 
@@ -595,7 +566,7 @@ private void updateComponents() {
                         Pattern.compile(s1);
                     } catch (PatternSyntaxException e) {
                         okEnabled = false;
-                        setDescription(formatRegExException(s1, e));
+                        setDescription(GroupDescriptions.formatRegexException(s1, e));
                     }
                 }
             } else {
@@ -635,16 +606,6 @@ private List<Path> getFileDirectoriesAsPaths() {
         return fileDirs;
     }
 
-    private String fromTextFlowToHTMLString(TextFlow textFlow) {
-        StringBuilder htmlStringBuilder = new StringBuilder();
-        for (Node node : textFlow.getChildren()) {
-            if (node instanceof Text) {
-                htmlStringBuilder.append(TooltipTextUtil.textToHTMLString((Text) node));
-            }
-        }
-        return htmlStringBuilder.toString();
-    }
-
     private boolean isRegex() {
         return searchGroupRegExp.isSelected();
     }
@@ -654,42 +615,7 @@ private boolean isCaseSensitive() {
     }
 
     private void setDescription(String description) {
-        descriptionTextFlow.getChildren().setAll(createFormattedDescription(description));
-    }
-
-    private ArrayList<Node> createFormattedDescription(String descriptionHTML) {
-        ArrayList<Node> nodes = new ArrayList<>();
-
-        descriptionHTML = descriptionHTML.replaceAll("<p>|<br>", "\n");
-
-        String[] boldSplit = descriptionHTML.split("(?=<b>)|(?<=</b>)|(?=<i>)|(?<=</i>)|(?=<tt>)|(?<=</tt>)|(?=<kbd>)|(?<=</kbd>)");
-
-        for (String bs : boldSplit) {
-
-            if (bs.matches("<b>[^<>]*</b>")) {
-
-                bs = bs.replaceAll("<b>|</b>", "");
-                Text textElement = new Text(bs);
-                textElement.setStyle("-fx-font-weight: bold");
-                nodes.add(textElement);
-            } else if (bs.matches("<i>[^<>]*</i>")) {
-
-                bs = bs.replaceAll("<i>|</i>", "");
-                Text textElement = new Text(bs);
-                textElement.setStyle("-fx-font-style: italic");
-                nodes.add(textElement);
-            } else if (bs.matches("<tt>[^<>]*</tt>|<kbd>[^<>]*</kbd>")) {
-
-                bs = bs.replaceAll("<tt>|</tt>|<kbd>|</kbd>", "");
-                Text textElement = new Text(bs);
-                textElement.setStyle("-fx-font-family: 'Courier New', Courier, monospace");
-                nodes.add(textElement);
-            } else {
-                nodes.add(new Text(bs));
-            }
-        }
-
-        return nodes;
+        descriptionTextFlow.getChildren().setAll(GroupDescriptions.createFormattedDescription(description));
     }
 
     /**
diff --git a/src/main/java/org/jabref/gui/groups/GroupDialogView.java b/src/main/java/org/jabref/gui/groups/GroupDialogView.java
index 5ac9f094532..eb7b84e1d14 100644
--- a/src/main/java/org/jabref/gui/groups/GroupDialogView.java
+++ b/src/main/java/org/jabref/gui/groups/GroupDialogView.java
@@ -1,13 +1,11 @@
 package org.jabref.gui.groups;
 
-import java.util.ArrayList;
 import java.util.regex.Pattern;
 import java.util.regex.PatternSyntaxException;
 
 import javafx.application.Platform;
 import javafx.event.ActionEvent;
 import javafx.fxml.FXML;
-import javafx.scene.Node;
 import javafx.scene.control.ButtonType;
 import javafx.scene.control.CheckBox;
 import javafx.scene.control.ColorPicker;
@@ -15,7 +13,6 @@
 import javafx.scene.control.RadioButton;
 import javafx.scene.control.TextField;
 import javafx.scene.input.KeyEvent;
-import javafx.scene.text.Text;
 import javafx.scene.text.TextFlow;
 
 import org.jabref.Globals;
@@ -25,13 +22,11 @@
 import org.jabref.gui.search.rules.describer.SearchDescribers;
 import org.jabref.gui.util.BaseDialog;
 import org.jabref.gui.util.IconValidationDecorator;
-import org.jabref.gui.util.TooltipTextUtil;
 import org.jabref.gui.util.ViewModelListCellFactory;
 import org.jabref.logic.l10n.Localization;
 import org.jabref.logic.search.SearchQuery;
 import org.jabref.model.groups.AbstractGroup;
 import org.jabref.model.groups.GroupHierarchyType;
-import org.jabref.model.strings.StringUtil;
 import org.jabref.preferences.JabRefPreferences;
 
 import com.airhacks.afterburner.views.ViewLoader;
@@ -233,7 +228,7 @@ private void updateComponents() {
                         setDescription(GroupDescriptions.getDescriptionForPreview(searchField, searchTerm, keywordGroupCaseSensitive.isSelected(),
                                 keywordGroupRegex.isSelected()));
                     } catch (PatternSyntaxException e) {
-                        setDescription(formatRegexException(searchTerm, e));
+                        setDescription(GroupDescriptions.formatRegexException(searchTerm, e));
                     }
                 } else {
                     setDescription(GroupDescriptions.getDescriptionForPreview(searchField, searchTerm, keywordGroupCaseSensitive.isSelected(),
@@ -246,7 +241,7 @@ private void updateComponents() {
         } else if (searchRadioButton.isSelected()) {
             searchTerm = searchGroupSearchTerm.getText().trim();
             if (!searchTerm.isEmpty()) {
-                setDescription(fromTextFlowToHTMLString(SearchDescribers
+                setDescription(GroupDescriptions.fromTextFlowToHTMLString(SearchDescribers
                         .getSearchDescriberFor(new SearchQuery(
                                 searchTerm,
                                 searchGroupCaseSensitive.isSelected(),
@@ -256,7 +251,7 @@ private void updateComponents() {
                     try {
                         Pattern.compile(searchTerm);
                     } catch (PatternSyntaxException e) {
-                        setDescription(formatRegexException(searchTerm, e));
+                        setDescription(GroupDescriptions.formatRegexException(searchTerm, e));
                     }
                 }
             } else {
@@ -272,77 +267,6 @@ private void updateComponents() {
     }
 
     private void setDescription(String description) {
-        hintTextFlow.getChildren().setAll(createFormattedDescription(description));
-    }
-
-    private ArrayList<Node> createFormattedDescription(String descriptionHTML) {
-        ArrayList<Node> nodes = new ArrayList<>();
-
-        descriptionHTML = descriptionHTML.replaceAll("<p>|<br>", "\n");
-
-        String[] boldSplit = descriptionHTML.split("(?=<b>)|(?<=</b>)|(?=<i>)|(?<=</i>)|(?=<tt>)|(?<=</tt>)|(?=<kbd>)|(?<=</kbd>)");
-
-        for (String bs : boldSplit) {
-
-            if (bs.matches("<b>[^<>]*</b>")) {
-
-                bs = bs.replaceAll("<b>|</b>", "");
-                Text textElement = new Text(bs);
-                textElement.setStyle("-fx-font-weight: bold");
-                nodes.add(textElement);
-            } else if (bs.matches("<i>[^<>]*</i>")) {
-
-                bs = bs.replaceAll("<i>|</i>", "");
-                Text textElement = new Text(bs);
-                textElement.setStyle("-fx-font-style: italic");
-                nodes.add(textElement);
-            } else if (bs.matches("<tt>[^<>]*</tt>|<kbd>[^<>]*</kbd>")) {
-
-                bs = bs.replaceAll("<tt>|</tt>|<kbd>|</kbd>", "");
-                Text textElement = new Text(bs);
-                textElement.setStyle("-fx-font-family: 'Courier New', Courier, monospace");
-                nodes.add(textElement);
-            } else {
-                nodes.add(new Text(bs));
-            }
-        }
-
-        return nodes;
-    }
-
-    private static String formatRegexException(String regExp, Exception e) {
-        String[] sa = e.getMessage().split("\\n");
-        StringBuilder sb = new StringBuilder();
-        for (int i = 0; i < sa.length; ++i) {
-            if (i > 0) {
-                sb.append("<br>");
-            }
-            sb.append(StringUtil.quoteForHTML(sa[i]));
-        }
-        String s = Localization.lang(
-                "The regular expression <b>%0</b> is invalid:",
-                StringUtil.quoteForHTML(regExp))
-                + "<p><tt>"
-                + sb
-                + "</tt>";
-        if (!(e instanceof PatternSyntaxException)) {
-            return s;
-        }
-        int lastNewline = s.lastIndexOf("<br>");
-        int hat = s.lastIndexOf('^');
-        if ((lastNewline >= 0) && (hat >= 0) && (hat > lastNewline)) {
-            return s.substring(0, lastNewline + 4) + s.substring(lastNewline + 4).replace(" ", "&nbsp;");
-        }
-        return s;
-    }
-
-    private String fromTextFlowToHTMLString(TextFlow textFlow) {
-        StringBuilder htmlStringBuilder = new StringBuilder();
-        for (Node node : textFlow.getChildren()) {
-            if (node instanceof Text) {
-                htmlStringBuilder.append(TooltipTextUtil.textToHTMLString((Text) node));
-            }
-        }
-        return htmlStringBuilder.toString();
+        hintTextFlow.getChildren().setAll(GroupDescriptions.createFormattedDescription(description));
     }
 }

From bdfc99af09c6d362d35e28a2c40ca1b0fff15dce Mon Sep 17 00:00:00 2001
From: Carl Christian Snethlage <cc.snethlage@gmail.com>
Date: Sat, 18 Jan 2020 19:41:53 +0100
Subject: [PATCH 4/9] Removed description, fixed ok button and added some minor
 improvements

---
 CHANGELOG.md                                  |   2 +
 .../jabref/gui/groups/GroupDescriptions.java  | 111 ---
 .../org/jabref/gui/groups/GroupDialog.fxml    | 126 ++--
 .../org/jabref/gui/groups/GroupDialog.java    | 662 ------------------
 .../jabref/gui/groups/GroupDialogView.java    | 112 +--
 .../gui/groups/GroupDialogViewModel.java      |  60 +-
 .../java/org/jabref/logic/help/HelpFile.java  |   1 +
 src/main/resources/l10n/JabRef_en.properties  |  25 +-
 8 files changed, 101 insertions(+), 998 deletions(-)
 delete mode 100644 src/main/java/org/jabref/gui/groups/GroupDialog.java

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8489723adc4..7ca03f4d8e0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,8 @@ We refer to [GitHub issues](https://github.com/JabRef/jabref/issues) by using `#
 
 ### Changed
 
+- We cleaned up the group add/edit dialog. [#5826](https://github.com/JabRef/jabref/pull/5826)
+
 ### Fixed
 
 - We fixed an issue where the Medline fetcher was only working when JabRef was running from source [#5645](https://github.com/JabRef/jabref/issues/5645)
diff --git a/src/main/java/org/jabref/gui/groups/GroupDescriptions.java b/src/main/java/org/jabref/gui/groups/GroupDescriptions.java
index bfa28218171..cf45a498046 100644
--- a/src/main/java/org/jabref/gui/groups/GroupDescriptions.java
+++ b/src/main/java/org/jabref/gui/groups/GroupDescriptions.java
@@ -1,13 +1,5 @@
 package org.jabref.gui.groups;
 
-import java.util.ArrayList;
-import java.util.regex.PatternSyntaxException;
-
-import javafx.scene.Node;
-import javafx.scene.text.Text;
-import javafx.scene.text.TextFlow;
-
-import org.jabref.gui.util.TooltipTextUtil;
 import org.jabref.logic.l10n.Localization;
 import org.jabref.model.groups.ExplicitGroup;
 import org.jabref.model.groups.KeywordGroup;
@@ -19,29 +11,6 @@ public class GroupDescriptions {
     private GroupDescriptions() {
     }
 
-    public static String getDescriptionForPreview(String field, String expr, boolean caseSensitive, boolean regExp) {
-        String header = regExp ? Localization.lang(
-                "This group contains entries whose <b>%0</b> field contains the regular expression <b>%1</b>",
-                field, expr) : Localization.lang(
-                        "This group contains entries whose <b>%0</b> field contains the keyword <b>%1</b>",
-                        field, expr);
-        String caseSensitiveText = caseSensitive ? Localization.lang("case sensitive") : Localization
-                .lang("case insensitive");
-        String footer = regExp ? Localization
-                .lang("Entries cannot be manually assigned to or removed from this group.") : Localization.lang(
-                        "Additionally, entries whose <b>%0</b> field does not contain "
-                                + "<b>%1</b> can be assigned manually to this group by selecting them "
-                                + "then using either drag and drop or the context menu. "
-                                + "This process adds the term <b>%1</b> to "
-                                + "each entry's <b>%0</b> field. "
-                                + "Entries can be removed manually from this group by selecting them "
-                                + "then using the context menu. "
-                                + "This process removes the term <b>%1</b> from "
-                                + "each entry's <b>%0</b> field.",
-                        field, expr);
-        return String.format("%s (%s). %s", header, caseSensitiveText, footer);
-    }
-
     public static String getShortDescriptionKeywordGroup(KeywordGroup keywordGroup, boolean showDynamic) {
         StringBuilder sb = new StringBuilder();
         sb.append("<b>");
@@ -73,14 +42,6 @@ public static String getShortDescriptionKeywordGroup(KeywordGroup keywordGroup,
 
     }
 
-    public static String getDescriptionForPreview() {
-        return Localization.lang("This group contains entries based on manual assignment. "
-                + "Entries can be assigned to this group by selecting them "
-                + "then using either drag and drop or the context menu. "
-                + "Entries can be removed from this group by selecting them "
-                + "then using the context menu.");
-    }
-
     public static String getShortDescriptionExplicitGroup(ExplicitGroup explicitGroup) {
         StringBuilder sb = new StringBuilder();
         sb.append("<b>").append(explicitGroup.getName()).append("</b> - ").append(Localization.lang("static group"));
@@ -126,76 +87,4 @@ public static String getShortDescription(SearchGroup searchGroup, boolean showDy
         }
         return sb.toString();
     }
-
-    protected static String fromTextFlowToHTMLString(TextFlow textFlow) {
-        StringBuilder htmlStringBuilder = new StringBuilder();
-        for (Node node : textFlow.getChildren()) {
-            if (node instanceof Text) {
-                htmlStringBuilder.append(TooltipTextUtil.textToHTMLString((Text) node));
-            }
-        }
-        return htmlStringBuilder.toString();
-    }
-
-    protected static String formatRegexException(String regExp, Exception e) {
-        String[] sa = e.getMessage().split("\\n");
-        StringBuilder sb = new StringBuilder();
-        for (int i = 0; i < sa.length; ++i) {
-            if (i > 0) {
-                sb.append("<br>");
-            }
-            sb.append(StringUtil.quoteForHTML(sa[i]));
-        }
-        String s = Localization.lang(
-                "The regular expression <b>%0</b> is invalid:",
-                StringUtil.quoteForHTML(regExp))
-                + "<p><tt>"
-                + sb
-                + "</tt>";
-        if (!(e instanceof PatternSyntaxException)) {
-            return s;
-        }
-        int lastNewline = s.lastIndexOf("<br>");
-        int hat = s.lastIndexOf('^');
-        if ((lastNewline >= 0) && (hat >= 0) && (hat > lastNewline)) {
-            return s.substring(0, lastNewline + 4) + s.substring(lastNewline + 4).replace(" ", "&nbsp;");
-        }
-        return s;
-    }
-
-    protected static ArrayList<Node> createFormattedDescription(String descriptionHTML) {
-        ArrayList<Node> nodes = new ArrayList<>();
-
-        descriptionHTML = descriptionHTML.replaceAll("<p>|<br>", "\n");
-
-        String[] boldSplit = descriptionHTML.split("(?=<b>)|(?<=</b>)|(?=<i>)|(?<=</i>)|(?=<tt>)|(?<=</tt>)|(?=<kbd>)|(?<=</kbd>)");
-
-        for (String bs : boldSplit) {
-
-            if (bs.matches("<b>[^<>]*</b>")) {
-
-                bs = bs.replaceAll("<b>|</b>", "");
-                Text textElement = new Text(bs);
-                textElement.setStyle("-fx-font-weight: bold");
-                nodes.add(textElement);
-            } else if (bs.matches("<i>[^<>]*</i>")) {
-
-                bs = bs.replaceAll("<i>|</i>", "");
-                Text textElement = new Text(bs);
-                textElement.setStyle("-fx-font-style: italic");
-                nodes.add(textElement);
-            } else if (bs.matches("<tt>[^<>]*</tt>|<kbd>[^<>]*</kbd>")) {
-
-                bs = bs.replaceAll("<tt>|</tt>|<kbd>|</kbd>", "");
-                Text textElement = new Text(bs);
-                textElement.setStyle("-fx-font-family: 'Courier New', Courier, monospace");
-                nodes.add(textElement);
-            } else {
-                nodes.add(new Text(bs));
-            }
-        }
-
-        return nodes;
-    }
-
 }
diff --git a/src/main/java/org/jabref/gui/groups/GroupDialog.fxml b/src/main/java/org/jabref/gui/groups/GroupDialog.fxml
index 873dd355aa5..8b2b424ccf5 100644
--- a/src/main/java/org/jabref/gui/groups/GroupDialog.fxml
+++ b/src/main/java/org/jabref/gui/groups/GroupDialog.fxml
@@ -3,7 +3,7 @@
 <?import javafx.geometry.Insets?>
 <?import javafx.scene.control.*?>
 <?import javafx.scene.layout.*?>
-<?import javafx.scene.text.TextFlow?>
+<?import org.jabref.gui.icon.JabRefIconView?>
 
 <DialogPane prefHeight="300.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/10.0.2-internal"
             xmlns:fx="http://javafx.com/fxml/1" fx:controller="org.jabref.gui.groups.GroupDialogView">
@@ -39,7 +39,7 @@
                     <ComboBox fx:id="hierarchicalContextCombo" minWidth="130.0" maxWidth="130.0" prefWidth="130.0"/>
                 </VBox>
             </HBox>
-            <HBox spacing="4.0">
+            <HBox>
                 <VBox spacing="10.0">
                     <Label text="%Collect by"/>
                     <RadioButton fx:id="explicitRadioButton" toggleGroup="$type" wrapText="true"
@@ -74,76 +74,82 @@
                     </RadioButton>
                 </VBox>
                 <Separator orientation="VERTICAL"/>
-                <VBox HBox.hgrow="ALWAYS">
-                    <StackPane>
-                        <VBox visible="${keywordsRadioButton.selected}" spacing="10.0">
+                <StackPane HBox.hgrow="ALWAYS">
+                    <VBox visible="${keywordsRadioButton.selected}" spacing="10.0">
+                        <VBox>
                             <Label text="%Field"/>
                             <TextField fx:id="keywordGroupSearchField"/>
+                        </VBox>
+                        <VBox>
                             <Label text="%Keyword"/>
                             <TextField fx:id="keywordGroupSearchTerm"/>
-                            <HBox alignment="CENTER" spacing="10.0">
-                                <CheckBox fx:id="keywordGroupCaseSensitive" text="Case sensitive"/>
-                                <CheckBox fx:id="keywordGroupRegex" text="Regular expression"/>
-                            </HBox>
                         </VBox>
-                        <VBox visible="${searchRadioButton.selected}" spacing="10.0">
+                        <HBox spacing="10.0">
+                            <CheckBox fx:id="keywordGroupCaseSensitive" text="Case sensitive"/>
+                            <CheckBox fx:id="keywordGroupRegex" text="Regular expression"/>
+                        </HBox>
+                    </VBox>
+                    <VBox visible="${searchRadioButton.selected}" spacing="4.0">
+                        <VBox>
                             <Label text="%Search expression"/>
                             <TextField fx:id="searchGroupSearchTerm"/>
-                            <HBox alignment="CENTER" spacing="10.0">
-                                <CheckBox fx:id="searchGroupCaseSensitive" text="Case sensitive"/>
-                                <CheckBox fx:id="searchGroupRegex" text="Regular expression"/>
-                            </HBox>
                         </VBox>
-                        <VBox visible="${autoRadioButton.selected}" spacing="10.0">
-                            <RadioButton fx:id="autoGroupKeywordsOption" toggleGroup="$autoGroupOptions"
-                                         text="Generate groups from keywords in a BibTeX field"/>
-                            <VBox spacing="10.0">
-                                <padding>
-                                    <Insets left="20.0"/>
-                                </padding>
-                                <HBox spacing="10.0">
-                                    <VBox HBox.hgrow="ALWAYS">
-                                        <Label text="%Field to group by:"/>
-                                        <TextField fx:id="autoGroupKeywordsField"
+                        <HBox spacing="10.0">
+                            <CheckBox fx:id="searchGroupCaseSensitive" text="Case sensitive"/>
+                            <CheckBox fx:id="searchGroupRegex" text="Regular expression"/>
+                        </HBox>
+                    </VBox>
+                    <VBox visible="${autoRadioButton.selected}" spacing="4.0">
+                        <RadioButton fx:id="autoGroupKeywordsOption" toggleGroup="$autoGroupOptions"
+                                     text="Generate groups from keywords in a BibTeX field"/>
+                        <VBox spacing="10.0">
+                            <padding>
+                                <Insets left="20.0"/>
+                            </padding>
+                            <HBox spacing="4.0">
+                                <VBox HBox.hgrow="ALWAYS">
+                                    <Label text="%Field to group by:"/>
+                                    <TextField fx:id="autoGroupKeywordsField"
+                                               disable="${!autoGroupKeywordsOption.selected}"/>
+                                </VBox>
+                                <VBox>
+                                    <Label text="%Delimiter(s)"/>
+                                    <HBox spacing="10.0">
+                                        <TextField fx:id="autoGroupKeywordsDeliminator" prefWidth="25.0"
                                                    disable="${!autoGroupKeywordsOption.selected}"/>
-                                    </VBox>
-                                    <VBox>
-                                        <Label text="%Delimiter character(s):"/>
-                                        <HBox spacing="10.0">
-                                            <TextField fx:id="autoGroupKeywordsDeliminator" prefWidth="50.0"
-                                                       disable="${!autoGroupKeywordsOption.selected}"/>
-                                            <TextField fx:id="autoGroupKeywordsHierarchicalDeliminator" prefWidth="50.0"
-                                                       disable="${!autoGroupKeywordsOption.selected}"/>
-                                        </HBox>
-                                    </VBox>
-                                </HBox>
-                            </VBox>
-                            <RadioButton fx:id="autoGroupPersonsOption" toggleGroup="$autoGroupOptions"
-                                         text="Generate groups for author last names"/>
-                            <VBox>
-                                <padding>
-                                    <Insets left="20.0"/>
-                                </padding>
-                                <Label text="%Field to group by:"/>
-                                <TextField fx:id="autoGroupPersonsField" disable="${!autoGroupPersonsOption.selected}"/>
-                            </VBox>
+                                        <TextField fx:id="autoGroupKeywordsHierarchicalDeliminator" prefWidth="25.0"
+                                                   disable="${!autoGroupKeywordsOption.selected}"/>
+                                    </HBox>
+                                </VBox>
+                            </HBox>
                         </VBox>
-                        <VBox visible="${texRadioButton.selected}" spacing="10.0">
-                            <Label text="%Aux file"/>
-                            <VBox>
-                                <padding>
-                                    <Insets left="20.0"/>
-                                </padding>
-                                <HBox spacing="10.0">
-                                    <TextField fx:id="texGroupFilePath" HBox.hgrow="ALWAYS"/>
-                                    <Button onAction="#texGroupBrowse" text="%Browse"/>
-                                </HBox>
-                            </VBox>
+                        <RadioButton fx:id="autoGroupPersonsOption" toggleGroup="$autoGroupOptions"
+                                     text="Generate groups for author last names"/>
+                        <VBox>
+                            <padding>
+                                <Insets left="20.0"/>
+                            </padding>
+                            <Label text="%Field to group by:"/>
+                            <TextField fx:id="autoGroupPersonsField" disable="${!autoGroupPersonsOption.selected}"/>
                         </VBox>
-                    </StackPane>
-                </VBox>
+                    </VBox>
+                    <VBox visible="${texRadioButton.selected}">
+                        <Label text="%Aux file"/>
+                        <HBox spacing="10.0">
+                            <TextField fx:id="texGroupFilePath" HBox.hgrow="ALWAYS" prefHeight="30.0"/>
+                            <Button onAction="#texGroupBrowse" text="%Browse" prefHeight="30.0"/>
+                        </HBox>
+                    </VBox>
+                </StackPane>
+                <Button styleClass="icon-button,narrow" onAction="#openHelp">
+                    <graphic>
+                        <JabRefIconView glyph="HELP"/>
+                    </graphic>
+                    <tooltip>
+                        <Tooltip text="%Open Help page"/>
+                    </tooltip>
+                </Button>
             </HBox>
-            <TextFlow fx:id="hintTextFlow" VBox.vgrow="ALWAYS" minHeight="100.0" maxHeight="100.0" prefHeight="100.0"/>
         </VBox>
     </content>
 </DialogPane>
diff --git a/src/main/java/org/jabref/gui/groups/GroupDialog.java b/src/main/java/org/jabref/gui/groups/GroupDialog.java
deleted file mode 100644
index 79ba208797e..00000000000
--- a/src/main/java/org/jabref/gui/groups/GroupDialog.java
+++ /dev/null
@@ -1,662 +0,0 @@
-package org.jabref.gui.groups;
-
-import java.io.IOException;
-import java.nio.file.Path;
-import java.nio.file.Paths;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Optional;
-import java.util.regex.Pattern;
-import java.util.regex.PatternSyntaxException;
-
-import javafx.beans.value.ObservableValue;
-import javafx.event.ActionEvent;
-import javafx.event.EventHandler;
-import javafx.geometry.Insets;
-import javafx.geometry.Orientation;
-import javafx.scene.Node;
-import javafx.scene.control.Button;
-import javafx.scene.control.ButtonType;
-import javafx.scene.control.CheckBox;
-import javafx.scene.control.ColorPicker;
-import javafx.scene.control.Label;
-import javafx.scene.control.RadioButton;
-import javafx.scene.control.ScrollPane;
-import javafx.scene.control.ScrollPane.ScrollBarPolicy;
-import javafx.scene.control.Separator;
-import javafx.scene.control.TextField;
-import javafx.scene.control.Toggle;
-import javafx.scene.control.ToggleGroup;
-import javafx.scene.layout.HBox;
-import javafx.scene.layout.Priority;
-import javafx.scene.layout.StackPane;
-import javafx.scene.layout.VBox;
-import javafx.scene.text.Font;
-import javafx.scene.text.FontPosture;
-import javafx.scene.text.TextFlow;
-
-import org.jabref.Globals;
-import org.jabref.JabRefGUI;
-import org.jabref.gui.BasePanel;
-import org.jabref.gui.DialogService;
-import org.jabref.gui.icon.IconTheme;
-import org.jabref.gui.search.rules.describer.SearchDescribers;
-import org.jabref.gui.util.BaseDialog;
-import org.jabref.gui.util.FileDialogConfiguration;
-import org.jabref.logic.auxparser.DefaultAuxParser;
-import org.jabref.logic.l10n.Localization;
-import org.jabref.logic.search.SearchQuery;
-import org.jabref.logic.util.StandardFileType;
-import org.jabref.logic.util.io.FileUtil;
-import org.jabref.model.database.BibDatabase;
-import org.jabref.model.entry.Keyword;
-import org.jabref.model.entry.field.FieldFactory;
-import org.jabref.model.entry.field.StandardField;
-import org.jabref.model.groups.AbstractGroup;
-import org.jabref.model.groups.AutomaticGroup;
-import org.jabref.model.groups.AutomaticKeywordGroup;
-import org.jabref.model.groups.AutomaticPersonsGroup;
-import org.jabref.model.groups.ExplicitGroup;
-import org.jabref.model.groups.GroupHierarchyType;
-import org.jabref.model.groups.GroupTreeNode;
-import org.jabref.model.groups.RegexKeywordGroup;
-import org.jabref.model.groups.SearchGroup;
-import org.jabref.model.groups.TexGroup;
-import org.jabref.model.groups.WordKeywordGroup;
-import org.jabref.model.metadata.MetaData;
-import org.jabref.preferences.JabRefPreferences;
-
-// import com.jfoenix.controls.JFXColorPicker;
-
-/**
- * Dialog for creating or modifying groups. Operates directly on the Vector
- * containing group information.
- */
-class GroupDialog extends BaseDialog<AbstractGroup> {
-
-    private static final int INDEX_EXPLICIT_GROUP = 0;
-    private static final int INDEX_KEYWORD_GROUP = 1;
-    private static final int INDEX_SEARCH_GROUP = 2;
-    private static final int INDEX_AUTO_GROUP = 3;
-    private static final int INDEX_TEX_GROUP = 4;
-
-    // for all types
-    private final TextField nameField = new TextField();
-    private final TextField descriptionField = new TextField();
-    //private final JFXColorPicker colorField = new JFXColorPicker();
-    private final ColorPicker colorField = new ColorPicker();
-    private final TextField iconField = new TextField();
-    private final RadioButton explicitRadioButton = new RadioButton(Localization.lang("Statically group entries by manual assignment"));
-    private final RadioButton keywordsRadioButton = new RadioButton(Localization.lang("Dynamically group entries by searching a field for a keyword"));
-    private final RadioButton searchRadioButton = new RadioButton(Localization.lang("Dynamically group entries by a free-form search expression"));
-    private final RadioButton autoRadioButton = new RadioButton(Localization.lang("Automatically create groups"));
-    private final RadioButton texRadioButton = new RadioButton(Localization.lang("Group containing entries cited in a given TeX file"));
-    private final RadioButton independentButton = new RadioButton(Localization.lang("Independent group: When selected, view only this group's entries"));
-    private final RadioButton intersectionButton = new RadioButton(Localization.lang("Refine supergroup: When selected, view entries contained in both this group and its supergroup"));
-    private final RadioButton unionButton = new RadioButton(Localization.lang("Include subgroups: When selected, view entries contained in this group or its subgroups"));
-    private final DialogService dialogService;
-    private final JabRefPreferences prefs;
-    private final BasePanel basePanel;
-
-    // for KeywordGroup
-    private final TextField keywordGroupSearchTerm = new TextField();
-    private final TextField keywordGroupSearchField = new TextField();
-    private final CheckBox keywordGroupCaseSensitive = new CheckBox(Localization.lang("Case sensitive"));
-    private final CheckBox keywordGroupRegExp = new CheckBox(Localization.lang("regular expression"));
-
-    // for SearchGroup
-    private final TextField searchGroupSearchExpression = new TextField();
-    private final CheckBox searchGroupCaseSensitive = new CheckBox(Localization.lang("Case sensitive"));
-    private final CheckBox searchGroupRegExp = new CheckBox(Localization.lang("regular expression"));
-
-    // for AutoGroup
-    private final RadioButton autoGroupKeywordsOption = new RadioButton(Localization.lang("Generate groups from keywords in a BibTeX field"));
-    private final TextField autoGroupKeywordsField = new TextField();
-    private final TextField autoGroupKeywordsDeliminator = new TextField();
-    private final TextField autoGroupKeywordsHierarchicalDeliminator = new TextField();
-    private final RadioButton autoGroupPersonsOption = new RadioButton(Localization.lang("Generate groups for author last names"));
-    private final TextField autoGroupPersonsField = new TextField();
-
-    // for TexGroup
-    private final TextField texGroupFilePath = new TextField();
-    private final Button texGroupBrowseButton = new Button("Browse");
-    private final HBox texGroupHBox = new HBox(10);
-
-    // for all types
-    private final TextFlow descriptionTextFlow = new TextFlow();
-    private final StackPane optionsPanel = new StackPane();
-
-
-    /**
-     * Shows a group add/edit dialog.
-     *
-     * @param editedGroup The group being edited, or null if a new group is to be
-     *                    created.
-     */
-    public GroupDialog(DialogService dialogService, BasePanel basePanel, JabRefPreferences prefs, AbstractGroup editedGroup) {
-
-        if (editedGroup == null) {
-            this.setTitle(Localization.lang("Add subgroup"));
-        } else {
-            this.setTitle(Localization.lang("Edit group"));
-        }
-
-        explicitRadioButton.setSelected(true);
-
-        descriptionTextFlow.setMinWidth(585);
-        descriptionTextFlow.setPrefWidth(585);
-        descriptionTextFlow.setMinHeight(180);
-        descriptionTextFlow.setPrefHeight(180);
-
-        this.dialogService = dialogService;
-        this.prefs = prefs;
-        this.basePanel = basePanel;
-
-        // set default values (overwritten if editedGroup != null)
-        keywordGroupSearchField.setText(prefs.get(JabRefPreferences.GROUPS_DEFAULT_FIELD));
-
-        // configure elements
-        ToggleGroup groupType = new ToggleGroup();
-        explicitRadioButton.setToggleGroup(groupType);
-        keywordsRadioButton.setToggleGroup(groupType);
-        searchRadioButton.setToggleGroup(groupType);
-        autoRadioButton.setToggleGroup(groupType);
-        texRadioButton.setToggleGroup(groupType);
-
-        // Build individual layout cards for each group
-        VBox explicitPanel = createOptionsExplicitGroup();
-        explicitPanel.setVisible(true);
-        VBox keywordPanel = createOptionsKeywordGroup();
-        VBox searchPanel = createOptionsSearchGroup();
-        VBox autoPanel = createOptionsAutoGroup();
-        VBox texPanel = createOptionsTexGroup();
-        optionsPanel.getChildren().addAll(explicitPanel, keywordPanel, searchPanel, autoPanel, texPanel);
-        optionsPanel.setPadding(new Insets(0, 0, 0, 10));
-
-        // ... for buttons panel
-        getDialogPane().getButtonTypes().setAll(ButtonType.OK, ButtonType.CANCEL);
-
-        // General information
-        VBox contextPanel = new VBox(10);
-        contextPanel.setPadding(new Insets(0, 0, 0, 10));
-        contextPanel.getChildren().setAll(
-                independentButton,
-                intersectionButton,
-                unionButton
-        );
-        ToggleGroup groupHierarchy = new ToggleGroup();
-        independentButton.setToggleGroup(groupHierarchy);
-        intersectionButton.setToggleGroup(groupHierarchy);
-        unionButton.setToggleGroup(groupHierarchy);
-
-        colorField.setMinHeight(20);
-        VBox generalPanel = new VBox(10);
-        generalPanel.getChildren().setAll(
-                new VBox(
-                        new Label(Localization.lang("Name")),
-                        nameField
-                ),
-                new VBox(
-                        new Label(Localization.lang("Description")),
-                        descriptionField
-                ),
-                new HBox(30,
-                        new VBox(
-                                new Label(Localization.lang("Icon")),
-                                iconField
-                        ),
-                        new VBox(
-                                new Label(Localization.lang("Color")),
-                                colorField
-                        )
-                ),
-                new VBox(5,
-                        new Label(Localization.lang("Hierarchical context")),
-                        contextPanel
-                )
-        );
-
-        VBox selectPanel = new VBox(10,
-                explicitRadioButton,
-                keywordsRadioButton,
-                searchRadioButton,
-                autoRadioButton,
-                texRadioButton
-        );
-        selectPanel.setPadding(new Insets(0, 0, 0, 10));
-
-        // Description panel
-        ScrollPane descriptionPane = new ScrollPane(descriptionTextFlow);
-        descriptionPane.setHbarPolicy(ScrollBarPolicy.AS_NEEDED);
-        descriptionPane.setVbarPolicy(ScrollBarPolicy.AS_NEEDED);
-
-        // create layout
-        HBox mainPanel = new HBox(15);
-        getDialogPane().setContent(mainPanel);
-        mainPanel.setPadding(new Insets(5, 15, 5, 15));
-        mainPanel.getChildren().setAll(
-                new VBox(5,
-                        generalPanel,
-                        new VBox(5,
-                                new Label(Localization.lang("Type")),
-                                selectPanel
-                        )
-                ),
-                new Separator(Orientation.VERTICAL),
-                new VBox(5,
-                        new VBox(
-                                new Label(Localization.lang("Options")),
-                                optionsPanel
-                        ),
-                        new Label(Localization.lang("Description")),
-                        descriptionPane
-                )
-        );
-
-        updateComponents();
-
-        // add listeners
-        groupType.selectedToggleProperty().addListener((ObservableValue<? extends Toggle> ov, Toggle old_Toggle,
-                                                        Toggle new_Toggle) -> {
-            int select = INDEX_EXPLICIT_GROUP;
-            if (groupType.getSelectedToggle() == explicitRadioButton) {
-                select = INDEX_EXPLICIT_GROUP;
-            } else if (groupType.getSelectedToggle() == keywordsRadioButton) {
-                select = INDEX_KEYWORD_GROUP;
-            } else if (groupType.getSelectedToggle() == searchRadioButton) {
-                select = INDEX_SEARCH_GROUP;
-            } else if (groupType.getSelectedToggle() == autoRadioButton) {
-                select = INDEX_AUTO_GROUP;
-            } else if (groupType.getSelectedToggle() == texRadioButton) {
-                select = INDEX_TEX_GROUP;
-            }
-            for (Node n : optionsPanel.getChildren()) {
-                n.setVisible(false);
-            }
-            optionsPanel.getChildren().get(select).setVisible(true);
-            updateComponents();
-        });
-
-        setResultConverter(button -> {
-            if (button == ButtonType.OK) {
-                AbstractGroup resultingGroup = null;
-                try {
-                    String groupName = nameField.getText().trim();
-                    if (explicitRadioButton.isSelected()) {
-                        Character keywordDelimiter = Globals.prefs.getKeywordDelimiter();
-                        if (groupName.contains(Character.toString(keywordDelimiter))) {
-                            dialogService.showWarningDialogAndWait(null, Localization.lang("The group name contains the keyword separator \"%0\" and thus probably does not work as expected.", Character.toString(keywordDelimiter)));
-                        }
-
-                        Optional<GroupTreeNode> rootGroup = basePanel.getBibDatabaseContext().getMetaData().getGroups();
-                        if (rootGroup.isPresent()) {
-                            int groupsWithSameName = rootGroup.get().findChildrenSatisfying(group -> group.getName().equals(groupName)).size();
-                            boolean warnAboutSameName = false;
-                            if ((editedGroup == null) && (groupsWithSameName > 0)) {
-                                // New group but there is already one group with the same name
-                                warnAboutSameName = true;
-                            }
-                            if ((editedGroup != null) && !editedGroup.getName().equals(groupName) && (groupsWithSameName > 0)) {
-                                // Edit group, changed name to something that is already present
-                                warnAboutSameName = true;
-                            }
-
-                            if (warnAboutSameName) {
-                                dialogService.showErrorDialogAndWait(Localization.lang("There exists already a group with the same name.", Character.toString(keywordDelimiter)));
-                                return null;
-                            }
-                        }
-
-                        resultingGroup = new ExplicitGroup(groupName, getContext(),
-                                keywordDelimiter);
-                    } else if (keywordsRadioButton.isSelected()) {
-                        // regex is correct, otherwise OK would have been disabled
-                        // therefore I don't catch anything here
-                        if (keywordGroupRegExp.isSelected()) {
-                            resultingGroup = new RegexKeywordGroup(groupName, getContext(),
-                                    FieldFactory.parseField(keywordGroupSearchField.getText().trim()), keywordGroupSearchTerm.getText().trim(),
-                                    keywordGroupCaseSensitive.isSelected());
-                        } else {
-                            resultingGroup = new WordKeywordGroup(groupName, getContext(),
-                                    FieldFactory.parseField(keywordGroupSearchField.getText().trim()), keywordGroupSearchTerm.getText().trim(),
-                                    keywordGroupCaseSensitive.isSelected(), Globals.prefs.getKeywordDelimiter(), false);
-                        }
-                    } else if (searchRadioButton.isSelected()) {
-                        resultingGroup = new SearchGroup(groupName, getContext(), searchGroupSearchExpression.getText().trim(),
-                                isCaseSensitive(), isRegex());
-                    } else if (autoRadioButton.isSelected()) {
-                        if (autoGroupKeywordsOption.isSelected()) {
-                            resultingGroup = new AutomaticKeywordGroup(
-                                    groupName, getContext(),
-                                    FieldFactory.parseField(autoGroupKeywordsField.getText().trim()),
-                                    autoGroupKeywordsDeliminator.getText().charAt(0),
-                                    autoGroupKeywordsHierarchicalDeliminator.getText().charAt(0));
-                        } else {
-                            resultingGroup = new AutomaticPersonsGroup(groupName, getContext(),
-                                    FieldFactory.parseField(autoGroupPersonsField.getText().trim()));
-                        }
-                    } else if (texRadioButton.isSelected()) {
-                        resultingGroup = TexGroup.create(groupName, getContext(),
-                                Paths.get(texGroupFilePath.getText().trim()), new DefaultAuxParser(new BibDatabase()), Globals.getFileUpdateMonitor(), basePanel.getBibDatabaseContext().getMetaData());
-                    }
-
-                    resultingGroup.setColor(colorField.getValue());
-                    resultingGroup.setDescription(descriptionField.getText());
-                    resultingGroup.setIconName(iconField.getText());
-                    return resultingGroup;
-                } catch (IllegalArgumentException | IOException exception) {
-                    dialogService.showErrorDialogAndWait(exception.getLocalizedMessage(), exception);
-                    return null;
-                }
-            }
-            return null;
-        });
-
-        nameField.textProperty().addListener((observable, oldValue, newValue) -> updateComponents());
-        keywordGroupSearchTerm.textProperty().addListener((observable, oldValue, newValue) -> updateComponents());
-        searchGroupSearchExpression.textProperty().addListener((observable, oldValue, newValue) -> updateComponents());
-
-        EventHandler<ActionEvent> actionHandler = (ActionEvent e) -> updateComponents();
-        nameField.setOnAction(actionHandler);
-        descriptionField.setOnAction(actionHandler);
-        iconField.setOnAction(actionHandler);
-        keywordGroupSearchField.setOnAction(actionHandler);
-        keywordGroupSearchTerm.setOnAction(actionHandler);
-        keywordGroupCaseSensitive.setOnAction(actionHandler);
-        keywordGroupRegExp.setOnAction(actionHandler);
-        searchGroupSearchExpression.setOnAction(actionHandler);
-        searchGroupRegExp.setOnAction(actionHandler);
-
-        // configure for current type
-        if (editedGroup == null) {
-            // creating new group -> defaults!
-            colorField.setValue(IconTheme.getDefaultGroupColor());
-            explicitRadioButton.setSelected(true);
-            setContext(GroupHierarchyType.INDEPENDENT);
-        } else {
-            nameField.setText(editedGroup.getName());
-            colorField.setValue(editedGroup.getColor().orElse(IconTheme.getDefaultGroupColor()));
-            descriptionField.setText(editedGroup.getDescription().orElse(""));
-            iconField.setText(editedGroup.getIconName().orElse(""));
-            setContext(editedGroup.getHierarchicalContext());
-
-            if (editedGroup.getClass() == WordKeywordGroup.class) {
-                WordKeywordGroup group = (WordKeywordGroup) editedGroup;
-                keywordGroupSearchField.setText(group.getSearchField().getName());
-                keywordGroupSearchTerm.setText(group.getSearchExpression());
-                keywordGroupCaseSensitive.setSelected(group.isCaseSensitive());
-                keywordGroupRegExp.setSelected(false);
-                keywordsRadioButton.setSelected(true);
-            } else if (editedGroup.getClass() == RegexKeywordGroup.class) {
-                RegexKeywordGroup group = (RegexKeywordGroup) editedGroup;
-                keywordGroupSearchField.setText(group.getSearchField().getName());
-                keywordGroupSearchTerm.setText(group.getSearchExpression());
-                keywordGroupCaseSensitive.setSelected(group.isCaseSensitive());
-                keywordGroupRegExp.setSelected(true);
-                keywordsRadioButton.setSelected(true);
-            } else if (editedGroup.getClass() == SearchGroup.class) {
-                SearchGroup group = (SearchGroup) editedGroup;
-                searchGroupSearchExpression.setText(group.getSearchExpression());
-                searchGroupCaseSensitive.setSelected(group.isCaseSensitive());
-                searchGroupRegExp.setSelected(group.isRegularExpression());
-                searchRadioButton.setSelected(true);
-            } else if (editedGroup.getClass() == ExplicitGroup.class) {
-                explicitRadioButton.setSelected(true);
-            } else if (editedGroup instanceof AutomaticGroup) {
-                autoRadioButton.setSelected(true);
-
-                if (editedGroup.getClass() == AutomaticKeywordGroup.class) {
-                    AutomaticKeywordGroup group = (AutomaticKeywordGroup) editedGroup;
-                    autoGroupKeywordsDeliminator.setText(group.getKeywordDelimiter().toString());
-                    autoGroupKeywordsHierarchicalDeliminator.setText(group.getKeywordHierarchicalDelimiter().toString());
-                    autoGroupKeywordsField.setText(group.getField().getName());
-                } else if (editedGroup.getClass() == AutomaticPersonsGroup.class) {
-                    AutomaticPersonsGroup group = (AutomaticPersonsGroup) editedGroup;
-                    autoGroupPersonsField.setText(group.getField().getName());
-                }
-            } else if (editedGroup.getClass() == TexGroup.class) {
-                texRadioButton.setSelected(true);
-
-                TexGroup group = (TexGroup) editedGroup;
-                texGroupFilePath.setText(group.getFilePath().toString());
-            }
-        }
-        getDialogPane().getScene().getWindow().sizeToScene();
-    }
-
-    public GroupDialog(DialogService dialogService) {
-        this(dialogService, JabRefGUI.getMainFrame().getCurrentBasePanel(), Globals.prefs, null);
-    }
-
-    public GroupDialog(DialogService dialogService, AbstractGroup editedGroup) {
-        this(dialogService, JabRefGUI.getMainFrame().getCurrentBasePanel(), Globals.prefs, editedGroup);
-    }
-
-    private VBox createOptionsTexGroup() {
-        VBox texPanel = new VBox();
-        texPanel.setVisible(false);
-        texPanel.getChildren().add(new Label(Localization.lang("Aux file")));
-        texGroupBrowseButton.setOnAction((ActionEvent e) -> openBrowseDialog());
-        texGroupHBox.getChildren().add(texGroupFilePath);
-        texGroupHBox.getChildren().add(texGroupBrowseButton);
-        HBox.setHgrow(texGroupFilePath, Priority.ALWAYS);
-        texPanel.getChildren().add(texGroupHBox);
-        return texPanel;
-    }
-
-    private VBox createOptionsAutoGroup() {
-        VBox autoPanel = new VBox(10);
-        autoPanel.setVisible(false);
-        ToggleGroup tg = new ToggleGroup();
-        autoGroupKeywordsOption.setToggleGroup(tg);
-        autoGroupPersonsOption.setToggleGroup(tg);
-        VBox fieldToGroupByKeywords = new VBox(
-                new Label(Localization.lang("Field to group by:")),
-                autoGroupKeywordsField
-        );
-        fieldToGroupByKeywords.setPadding(new Insets(0, 0, 0, 20));
-        VBox delimiterCharacters = new VBox(
-                new Label(Localization.lang("Use the following delimiter character(s):")),
-                new HBox(10,
-                        autoGroupKeywordsDeliminator,
-                        autoGroupKeywordsHierarchicalDeliminator
-                )
-        );
-        delimiterCharacters.setPadding(new Insets(0, 0, 0, 20));
-        VBox fieldToGroupByPersons = new VBox(
-                new Label(Localization.lang("Field to group by:")),
-                autoGroupPersonsField
-        );
-        fieldToGroupByPersons.setPadding(new Insets(0, 0, 0, 20));
-        autoPanel.getChildren().setAll(
-                autoGroupKeywordsOption,
-                fieldToGroupByKeywords,
-                delimiterCharacters,
-                autoGroupPersonsOption,
-                fieldToGroupByPersons
-        );
-        autoGroupKeywordsOption.setSelected(true);
-        autoGroupKeywordsField.setText(Globals.prefs.get(JabRefPreferences.GROUPS_DEFAULT_FIELD));
-        autoGroupKeywordsDeliminator.setText(Globals.prefs.get(JabRefPreferences.KEYWORD_SEPARATOR));
-        autoGroupKeywordsHierarchicalDeliminator.setText(Keyword.DEFAULT_HIERARCHICAL_DELIMITER.toString());
-        autoGroupPersonsField.setText(StandardField.AUTHOR.getName());
-        return autoPanel;
-    }
-
-    private VBox createOptionsSearchGroup() {
-        VBox searchPanel = new VBox(10);
-        searchPanel.setVisible(false);
-        searchPanel.getChildren().setAll(
-                new VBox(
-                        new Label(Localization.lang("Search expression")),
-                        searchGroupSearchExpression
-                ),
-                searchGroupCaseSensitive,
-                searchGroupRegExp
-        );
-        return searchPanel;
-    }
-
-    private VBox createOptionsExplicitGroup() {
-        return new VBox();
-    }
-
-    private VBox createOptionsKeywordGroup() {
-        VBox keywordPanel = new VBox(10);
-        keywordPanel.setVisible(false);
-        keywordPanel.getChildren().setAll(
-                new VBox(
-                        new Label(Localization.lang("Field")),
-                        keywordGroupSearchField
-                ),
-                new VBox(
-                        new Label(Localization.lang("Keyword")),
-                        keywordGroupSearchTerm
-                ),
-                keywordGroupCaseSensitive,
-                keywordGroupRegExp
-        );
-        return keywordPanel;
-    }
-
-    private void updateComponents() {
-        // all groups need a name
-        boolean okEnabled = !nameField.getText().trim().isEmpty();
-        if (!okEnabled) {
-            setDescription(Localization.lang("Please enter a name for the group."));
-            getDialogPane().lookupButton(ButtonType.OK).setDisable(true);
-            return;
-        }
-        String s1;
-        String s2;
-        if (keywordsRadioButton.isSelected()) {
-            s1 = keywordGroupSearchField.getText().trim();
-            okEnabled = okEnabled && s1.matches("\\w+");
-            s2 = keywordGroupSearchTerm.getText().trim();
-            okEnabled = okEnabled && !s2.isEmpty();
-            if (okEnabled) {
-                if (keywordGroupRegExp.isSelected()) {
-                    try {
-                        Pattern.compile(s2);
-                        setDescription(GroupDescriptions.getDescriptionForPreview(s1, s2, keywordGroupCaseSensitive.isSelected(),
-                                keywordGroupRegExp.isSelected()));
-                    } catch (PatternSyntaxException e) {
-                        okEnabled = false;
-                        setDescription(GroupDescriptions.formatRegexException(s2, e));
-                    }
-                } else {
-                    setDescription(GroupDescriptions.getDescriptionForPreview(s1, s2, keywordGroupCaseSensitive.isSelected(),
-                            keywordGroupRegExp.isSelected()));
-                }
-            } else {
-                setDescription(Localization.lang(
-                        "Please enter the field to search (e.g. <b>keywords</b>) and the keyword to search it for (e.g. <b>electrical</b>)."));
-            }
-            setNameFontItalic(true);
-        } else if (searchRadioButton.isSelected()) {
-            s1 = searchGroupSearchExpression.getText().trim();
-            okEnabled = okEnabled & !s1.isEmpty();
-            if (okEnabled) {
-                setDescription(GroupDescriptions.fromTextFlowToHTMLString(SearchDescribers.getSearchDescriberFor(
-                        new SearchQuery(s1, isCaseSensitive(), isRegex()))
-                                                                        .getDescription()));
-
-                if (isRegex()) {
-                    try {
-                        Pattern.compile(s1);
-                    } catch (PatternSyntaxException e) {
-                        okEnabled = false;
-                        setDescription(GroupDescriptions.formatRegexException(s1, e));
-                    }
-                }
-            } else {
-                setDescription(Localization
-                        .lang("Please enter a search term. For example, to search all fields for <b>Smith</b>, enter:<p>"
-                                + "<tt>smith</tt><p>"
-                                + "To search the field <b>Author</b> for <b>Smith</b> and the field <b>Title</b> for <b>electrical</b>, enter:<p>"
-                                + "<tt>author=smith and title=electrical</tt>"));
-            }
-            setNameFontItalic(true);
-        } else if (explicitRadioButton.isSelected()) {
-            setDescription(GroupDescriptions.getDescriptionForPreview());
-            setNameFontItalic(false);
-        }
-        getDialogPane().lookupButton(ButtonType.OK).setDisable(!okEnabled);
-    }
-
-    private void openBrowseDialog() {
-        FileDialogConfiguration fileDialogConfiguration = new FileDialogConfiguration.Builder()
-                .addExtensionFilter(StandardFileType.AUX)
-                .withDefaultExtension(StandardFileType.AUX)
-                .withInitialDirectory(Globals.prefs.get(JabRefPreferences.WORKING_DIRECTORY)).build();
-        dialogService.showFileOpenDialog(fileDialogConfiguration).ifPresent(file -> texGroupFilePath.setText(relativize(file.toAbsolutePath()).toString()));
-    }
-
-    private Path relativize(Path path) {
-        List<Path> fileDirectories = getFileDirectoriesAsPaths();
-        return FileUtil.relativize(path, fileDirectories);
-    }
-
-    private List<Path> getFileDirectoriesAsPaths() {
-        List<Path> fileDirs = new ArrayList<>();
-        MetaData metaData = basePanel.getBibDatabaseContext().getMetaData();
-        metaData.getLaTexFileDirectory(prefs.getFilePreferences().getUser())
-                .ifPresent(laTexFileDirectory -> fileDirs.add(laTexFileDirectory));
-
-        return fileDirs;
-    }
-
-    private boolean isRegex() {
-        return searchGroupRegExp.isSelected();
-    }
-
-    private boolean isCaseSensitive() {
-        return searchGroupCaseSensitive.isSelected();
-    }
-
-    private void setDescription(String description) {
-        descriptionTextFlow.getChildren().setAll(GroupDescriptions.createFormattedDescription(description));
-    }
-
-    /**
-     * Sets the font of the name entry field.
-     */
-    private void setNameFontItalic(boolean italic) {
-        Font f = nameField.getFont();
-        if (italic) {
-            Font.font(f.getFamily(), FontPosture.ITALIC, f.getSize());
-        } else {
-            Font.font(f.getFamily(), FontPosture.REGULAR, f.getSize());
-        }
-    }
-
-    /**
-     * Returns the int representing the selected hierarchical group context.
-     */
-    private GroupHierarchyType getContext() {
-        if (independentButton.isSelected()) {
-            return GroupHierarchyType.INDEPENDENT;
-        }
-        if (intersectionButton.isSelected()) {
-            return GroupHierarchyType.REFINING;
-        }
-        if (unionButton.isSelected()) {
-            return GroupHierarchyType.INCLUDING;
-        }
-        return GroupHierarchyType.INDEPENDENT; // default
-    }
-
-    private void setContext(GroupHierarchyType context) {
-        switch (context) {
-            case INDEPENDENT:
-                independentButton.setSelected(true);
-                break;
-            case REFINING:
-                intersectionButton.setSelected(true);
-                break;
-            case INCLUDING:
-                unionButton.setSelected(true);
-                break;
-        }
-    }
-}
diff --git a/src/main/java/org/jabref/gui/groups/GroupDialogView.java b/src/main/java/org/jabref/gui/groups/GroupDialogView.java
index eb7b84e1d14..57643a7ab68 100644
--- a/src/main/java/org/jabref/gui/groups/GroupDialogView.java
+++ b/src/main/java/org/jabref/gui/groups/GroupDialogView.java
@@ -1,10 +1,6 @@
 package org.jabref.gui.groups;
 
-import java.util.regex.Pattern;
-import java.util.regex.PatternSyntaxException;
-
 import javafx.application.Platform;
-import javafx.event.ActionEvent;
 import javafx.fxml.FXML;
 import javafx.scene.control.ButtonType;
 import javafx.scene.control.CheckBox;
@@ -12,19 +8,15 @@
 import javafx.scene.control.ComboBox;
 import javafx.scene.control.RadioButton;
 import javafx.scene.control.TextField;
-import javafx.scene.input.KeyEvent;
-import javafx.scene.text.TextFlow;
 
 import org.jabref.Globals;
 import org.jabref.JabRefGUI;
 import org.jabref.gui.BasePanel;
 import org.jabref.gui.DialogService;
-import org.jabref.gui.search.rules.describer.SearchDescribers;
 import org.jabref.gui.util.BaseDialog;
 import org.jabref.gui.util.IconValidationDecorator;
 import org.jabref.gui.util.ViewModelListCellFactory;
 import org.jabref.logic.l10n.Localization;
-import org.jabref.logic.search.SearchQuery;
 import org.jabref.model.groups.AbstractGroup;
 import org.jabref.model.groups.GroupHierarchyType;
 import org.jabref.preferences.JabRefPreferences;
@@ -67,17 +59,11 @@ public class GroupDialogView extends BaseDialog<AbstractGroup> {
 
     @FXML private TextField texGroupFilePath;
 
-    // Description text
-    @FXML private TextFlow hintTextFlow;
-
     private final ControlsFxVisualizer validationVisualizer = new ControlsFxVisualizer();
     private final GroupDialogViewModel viewModel;
 
-    private final boolean showHints;
-
     public GroupDialogView(DialogService dialogService, BasePanel basePanel, JabRefPreferences prefs, AbstractGroup editedGroup) {
         viewModel = new GroupDialogViewModel(dialogService, basePanel, prefs, editedGroup);
-        this.showHints = prefs.getBoolean(JabRefPreferences.SHOW_ADVANCED_HINTS);
 
         ViewLoader.view(this)
                   .load()
@@ -86,14 +72,9 @@ public GroupDialogView(DialogService dialogService, BasePanel basePanel, JabRefP
         if (editedGroup == null) {
             this.setTitle(Localization.lang("Add subgroup"));
         } else {
-            this.setTitle(Localization.lang("Edit group"));
+            this.setTitle(Localization.lang("Edit group") + " " + editedGroup.getName());
         }
 
-        if (showHints) {
-            hintTextFlow.setPrefHeight(0d);
-        }
-        hintTextFlow.setVisible(showHints);
-
         setResultConverter(viewModel::resultConverter);
 
         getDialogPane().getButtonTypes().setAll(ButtonType.OK, ButtonType.CANCEL);
@@ -170,8 +151,6 @@ public void initialize() {
 
         texGroupFilePath.textProperty().bindBidirectional(viewModel.texGroupFilePathProperty());
 
-        hintTextFlow.accessibleTextProperty().bindBidirectional(viewModel.hintTextProperty());
-
         validationVisualizer.setDecoration(new IconValidationDecorator());
         Platform.runLater(() -> {
             validationVisualizer.initVisualization(viewModel.nameValidationStatus(), nameField);
@@ -183,25 +162,14 @@ public void initialize() {
             validationVisualizer.initVisualization(viewModel.keywordSearchTermEmptyValidationStatus(), keywordGroupSearchTerm);
         });
 
-        // ToDo: This comes straight from hell
-
-        nameField.textProperty().addListener((obs, oldval, newval) -> updateComponents());
-        keywordGroupSearchTerm.textProperty().addListener((obs, oldval, newval) -> updateComponents());
-        searchGroupSearchTerm.textProperty().addListener((obs, oldval, newval) -> updateComponents());
-
-        nameField.addEventHandler(KeyEvent.KEY_RELEASED, e -> updateComponents());
-        descriptionField.addEventHandler(KeyEvent.KEY_RELEASED, e -> updateComponents());
-        iconField.addEventHandler(KeyEvent.KEY_RELEASED, e -> updateComponents());
-        keywordGroupSearchField.addEventHandler(KeyEvent.KEY_RELEASED, e -> updateComponents());
-        keywordGroupSearchTerm.addEventHandler(KeyEvent.KEY_RELEASED, e -> updateComponents());
-        keywordGroupCaseSensitive.addEventHandler(ActionEvent.ANY, e -> updateComponents());
-        keywordGroupRegex.addEventHandler(ActionEvent.ANY, e -> updateComponents());
-        searchGroupSearchTerm.addEventHandler(ActionEvent.ANY, e -> updateComponents());
-        searchGroupCaseSensitive.addEventHandler(ActionEvent.ANY, e -> updateComponents());
-        searchGroupRegex.addEventHandler(ActionEvent.ANY, e -> updateComponents());
-
-        // NPE
-        // getDialogPane().lookupButton(ButtonType.OK).disableProperty().bind(viewModel.validationStatus().validProperty().not());
+        // Binding to the validProperty throws an NPE, so we have to work around this issue
+        viewModel.validationStatus().validProperty().addListener((obs, oldValue, newValue) -> {
+            if (newValue) {
+                getDialogPane().lookupButton(ButtonType.OK).setDisable(false);
+            } else {
+                getDialogPane().lookupButton(ButtonType.OK).setDisable(true);
+            }
+        });
     }
 
     @FXML
@@ -209,64 +177,8 @@ private void texGroupBrowse() {
         viewModel.texGroupBrowse();
     }
 
-    // ToDo: The following lines NEED to be changed!
-
-    private void updateComponents() {
-        if (!showHints) {
-            return;
-        }
-
-        String searchField;
-        String searchTerm;
-        if (keywordsRadioButton.isSelected()) {
-            searchField = keywordGroupSearchField.getText().trim();
-            searchTerm = keywordGroupSearchTerm.getText().trim();
-            if (searchField.matches("\\w+") && !searchTerm.isEmpty()) {
-                if (keywordGroupRegex.isSelected()) {
-                    try {
-                        Pattern.compile(searchTerm);
-                        setDescription(GroupDescriptions.getDescriptionForPreview(searchField, searchTerm, keywordGroupCaseSensitive.isSelected(),
-                                keywordGroupRegex.isSelected()));
-                    } catch (PatternSyntaxException e) {
-                        setDescription(GroupDescriptions.formatRegexException(searchTerm, e));
-                    }
-                } else {
-                    setDescription(GroupDescriptions.getDescriptionForPreview(searchField, searchTerm, keywordGroupCaseSensitive.isSelected(),
-                            keywordGroupRegex.isSelected()));
-                }
-            } else {
-                setDescription(Localization.lang(
-                        "Please enter the field to search (e.g. <b>keywords</b>) and the keyword to search it for (e.g. <b>electrical</b>)."));
-            }
-        } else if (searchRadioButton.isSelected()) {
-            searchTerm = searchGroupSearchTerm.getText().trim();
-            if (!searchTerm.isEmpty()) {
-                setDescription(GroupDescriptions.fromTextFlowToHTMLString(SearchDescribers
-                        .getSearchDescriberFor(new SearchQuery(
-                                searchTerm,
-                                searchGroupCaseSensitive.isSelected(),
-                                searchGroupRegex.isSelected()))
-                        .getDescription()));
-                if (searchGroupRegex.isSelected()) {
-                    try {
-                        Pattern.compile(searchTerm);
-                    } catch (PatternSyntaxException e) {
-                        setDescription(GroupDescriptions.formatRegexException(searchTerm, e));
-                    }
-                }
-            } else {
-                setDescription(Localization
-                        .lang("Please enter a search term. For example, to search all fields for <b>Smith</b>, enter:<p>"
-                                + "<tt>smith</tt><p>"
-                                + "To search the field <b>Author</b> for <b>Smith</b> and the field <b>Title</b> for <b>electrical</b>, enter:<p>"
-                                + "<tt>author=smith and title=electrical</tt>"));
-            }
-        } else if (explicitRadioButton.isSelected()) {
-            setDescription(GroupDescriptions.getDescriptionForPreview());
-        }
-    }
-
-    private void setDescription(String description) {
-        hintTextFlow.getChildren().setAll(GroupDescriptions.createFormattedDescription(description));
+    @FXML
+    private void openHelp() {
+        viewModel.openHelpPage();
     }
 }
diff --git a/src/main/java/org/jabref/gui/groups/GroupDialogViewModel.java b/src/main/java/org/jabref/gui/groups/GroupDialogViewModel.java
index 2034d81a05c..4d3101be4d6 100644
--- a/src/main/java/org/jabref/gui/groups/GroupDialogViewModel.java
+++ b/src/main/java/org/jabref/gui/groups/GroupDialogViewModel.java
@@ -24,9 +24,11 @@
 import org.jabref.Globals;
 import org.jabref.gui.BasePanel;
 import org.jabref.gui.DialogService;
+import org.jabref.gui.help.HelpAction;
 import org.jabref.gui.icon.IconTheme;
 import org.jabref.gui.util.FileDialogConfiguration;
 import org.jabref.logic.auxparser.DefaultAuxParser;
+import org.jabref.logic.help.HelpFile;
 import org.jabref.logic.l10n.Localization;
 import org.jabref.logic.util.StandardFileType;
 import org.jabref.logic.util.io.FileUtil;
@@ -89,9 +91,6 @@ public class GroupDialogViewModel {
 
     private final StringProperty texGroupFilePathProperty = new SimpleStringProperty("");
 
-    // Description text
-    private final StringProperty hintTextProperty = new SimpleStringProperty("");
-
     private Validator nameValidator;
     private Validator nameContainsDelimiterValidator;
     private Validator sameNameValidator;
@@ -99,7 +98,7 @@ public class GroupDialogViewModel {
     private Validator keywordSearchTermEmptyValidator;
     private Validator searchRegexValidator;
     private Validator searchSearchTermEmptyValidator;
-    private CompositeValidator validator;
+    private CompositeValidator validator = new CompositeValidator();
 
     private final DialogService dialogService;
     private final JabRefPreferences preferences;
@@ -173,11 +172,10 @@ private void setupValidation() {
                         return false;
                     }
                 },
-                ValidationMessage.error(String.format("%s > %n %s %n %n %s %n %s",
+                ValidationMessage.error(String.format("%s > %n %s %n %n %s",
                         Localization.lang("Searching for keywords"),
                         Localization.lang("Keywords"),
-                        Localization.lang("Invalid regular expression:"),
-                        keywordGroupSearchTermProperty.getValue())));
+                        Localization.lang("Invalid regular expression."))));
 
         keywordSearchTermEmptyValidator = new FunctionBasedValidator<>(
                 keywordGroupSearchTermProperty,
@@ -206,10 +204,9 @@ private void setupValidation() {
                         return false;
                     }
                 },
-                ValidationMessage.error(String.format("%s > %n %s %n %s",
+                ValidationMessage.error(String.format("%s > %n %s",
                         Localization.lang("Free search expression"),
-                        Localization.lang("Invalid regular expression:"),
-                        searchGroupSearchTermProperty.getValue())));
+                        Localization.lang("Invalid regular expression."))));
 
         searchSearchTermEmptyValidator = new FunctionBasedValidator<>(
                 searchGroupSearchTermProperty,
@@ -219,7 +216,7 @@ private void setupValidation() {
                         Localization.lang("Search term is empty.")
                 )));
 
-        validator = new CompositeValidator(nameValidator,sameNameValidator);
+        validator.addValidators(nameValidator, sameNameValidator);
 
         typeSearchProperty.addListener((obs,oldVal,newVal) -> {
             if (newVal) {
@@ -336,51 +333,32 @@ public void setValues() {
             groupHierarchySelectedProperty.setValue(editedGroup.getHierarchicalContext());
 
             if (editedGroup.getClass() == WordKeywordGroup.class) {
+                typeKeywordsProperty.setValue(true);
+
                 WordKeywordGroup group = (WordKeywordGroup) editedGroup;
                 keywordGroupSearchFieldProperty.setValue(group.getSearchField().getName());
                 keywordGroupSearchTermProperty.setValue(group.getSearchExpression());
                 keywordGroupCaseSensitiveProperty.setValue(group.isCaseSensitive());
                 keywordGroupRegexProperty.setValue(false);
-
-                typeExplicitProperty.setValue(false);
-                typeKeywordsProperty.setValue(true);
-                typeSearchProperty.setValue(false);
-                typeAutoProperty.setValue(false);
-                typeTexProperty.setValue(false);
             } else if (editedGroup.getClass() == RegexKeywordGroup.class) {
+                typeKeywordsProperty.setValue(true);
+
                 RegexKeywordGroup group = (RegexKeywordGroup) editedGroup;
                 keywordGroupSearchFieldProperty.setValue(group.getSearchField().getName());
                 keywordGroupSearchTermProperty.setValue(group.getSearchExpression());
                 keywordGroupCaseSensitiveProperty.setValue(group.isCaseSensitive());
                 keywordGroupRegexProperty.setValue(true);
-
-                typeExplicitProperty.setValue(false);
-                typeKeywordsProperty.setValue(true);
-                typeSearchProperty.setValue(false);
-                typeAutoProperty.setValue(false);
-                typeTexProperty.setValue(false);
             } else if (editedGroup.getClass() == SearchGroup.class) {
+                typeSearchProperty.setValue(true);
+
                 SearchGroup group = (SearchGroup) editedGroup;
                 searchGroupSearchTermProperty.setValue(group.getSearchExpression());
                 searchGroupCaseSensitiveProperty.setValue(group.isCaseSensitive());
                 searchGroupRegexProperty.setValue(group.isRegularExpression());
-
-                typeExplicitProperty.setValue(false);
-                typeKeywordsProperty.setValue(false);
-                typeSearchProperty.setValue(true);
-                typeAutoProperty.setValue(false);
-                typeTexProperty.setValue(false);
             } else if (editedGroup.getClass() == ExplicitGroup.class) {
                 typeExplicitProperty.setValue(true);
-                typeKeywordsProperty.setValue(false);
-                typeSearchProperty.setValue(false);
-                typeAutoProperty.setValue(false);
             } else if (editedGroup instanceof AutomaticGroup) {
-                typeExplicitProperty.setValue(false);
-                typeKeywordsProperty.setValue(false);
-                typeSearchProperty.setValue(false);
                 typeAutoProperty.setValue(true);
-                typeTexProperty.setValue(false);
 
                 if (editedGroup.getClass() == AutomaticKeywordGroup.class) {
                     AutomaticKeywordGroup group = (AutomaticKeywordGroup) editedGroup;
@@ -392,10 +370,6 @@ public void setValues() {
                     autoGroupPersonsFieldProperty.setValue(group.getField().getName());
                 }
             } else if (editedGroup.getClass() == TexGroup.class) {
-                typeExplicitProperty.setValue(false);
-                typeKeywordsProperty.setValue(false);
-                typeSearchProperty.setValue(false);
-                typeAutoProperty.setValue(false);
                 typeTexProperty.setValue(true);
 
                 TexGroup group = (TexGroup) editedGroup;
@@ -415,6 +389,10 @@ public void texGroupBrowse() {
                      ));
     }
 
+    public void openHelpPage() {
+        HelpAction.openHelpPage(HelpFile.GROUPS);
+    }
+
     private List<Path> getFileDirectoriesAsPaths() {
         List<Path> fileDirs = new ArrayList<>();
         MetaData metaData = basePanel.getBibDatabaseContext().getMetaData();
@@ -488,6 +466,4 @@ private List<Path> getFileDirectoriesAsPaths() {
     public StringProperty autoGroupPersonsFieldProperty() { return autoGroupPersonsFieldProperty; }
 
     public StringProperty texGroupFilePathProperty() { return texGroupFilePathProperty; }
-
-    public StringProperty hintTextProperty() { return hintTextProperty; }
 }
diff --git a/src/main/java/org/jabref/logic/help/HelpFile.java b/src/main/java/org/jabref/logic/help/HelpFile.java
index 6e5ce34fc12..b08b088c510 100644
--- a/src/main/java/org/jabref/logic/help/HelpFile.java
+++ b/src/main/java/org/jabref/logic/help/HelpFile.java
@@ -10,6 +10,7 @@ public enum HelpFile {
     CONTENTS(""), // this is always the index
     ENTRY_EDITOR("general/entryeditor"),
     STRING_EDITOR("setup/stringeditor"),
+    GROUPS("finding-sorting-and-cleaning-entries/groups#groups-structure-creating-and-removing-groups"),
     SPECIAL_FIELDS("fields/specialfields"),
     BIBTEX_KEY_PATTERN("setup/bibtexkeypatterns"),
     OWNER("fields/owner"),
diff --git a/src/main/resources/l10n/JabRef_en.properties b/src/main/resources/l10n/JabRef_en.properties
index f04e3bae199..bc2ccc8a1fd 100644
--- a/src/main/resources/l10n/JabRef_en.properties
+++ b/src/main/resources/l10n/JabRef_en.properties
@@ -49,8 +49,6 @@ Added\ group\ "%0".=Added group "%0".
 
 Added\ string=Added string
 
-Additionally,\ entries\ whose\ <b>%0</b>\ field\ does\ not\ contain\ <b>%1</b>\ can\ be\ assigned\ manually\ to\ this\ group\ by\ selecting\ them\ then\ using\ either\ drag\ and\ drop\ or\ the\ context\ menu.\ This\ process\ adds\ the\ term\ <b>%1</b>\ to\ each\ entry's\ <b>%0</b>\ field.\ Entries\ can\ be\ removed\ manually\ from\ this\ group\ by\ selecting\ them\ then\ using\ the\ context\ menu.\ This\ process\ removes\ the\ term\ <b>%1</b>\ from\ each\ entry's\ <b>%0</b>\ field.=Additionally, entries whose <b>%0</b> field does not contain <b>%1</b> can be assigned manually to this group by selecting them then using either drag and drop or the context menu. This process adds the term <b>%1</b> to each entry's <b>%0</b> field. Entries can be removed manually from this group by selecting them then using the context menu. This process removes the term <b>%1</b> from each entry's <b>%0</b> field.
-
 Advanced=Advanced
 All\ entries=All entries
 All\ entries\ of\ this\ type\ will\ be\ declared\ typeless.\ Continue?=All entries of this type will be declared typeless. Continue?
@@ -290,11 +288,8 @@ Enter\ URL\ to\ download=Enter URL to download
 
 entries=entries
 
-Entries\ cannot\ be\ manually\ assigned\ to\ or\ removed\ from\ this\ group.=Entries cannot be manually assigned to or removed from this group.
-
 Entries\ exported\ to\ clipboard=Entries exported to clipboard
 
-
 entry=entry
 
 Entry\ editor=Entry editor
@@ -639,10 +634,6 @@ File\ has\ no\ attached\ annotations=File has no attached annotations
 
 Please\ enter\ a\ name\ for\ the\ group.=Please enter a name for the group.
 
-Please\ enter\ a\ search\ term.\ For\ example,\ to\ search\ all\ fields\ for\ <b>Smith</b>,\ enter\:<p><tt>smith</tt><p>To\ search\ the\ field\ <b>Author</b>\ for\ <b>Smith</b>\ and\ the\ field\ <b>Title</b>\ for\ <b>electrical</b>,\ enter\:<p><tt>author\=smith\ and\ title\=electrical</tt>=Please enter a search term. For example, to search all fields for <b>Smith</b>, enter:<p><tt>smith</tt><p>To search the field <b>Author</b> for <b>Smith</b> and the field <b>Title</b> for <b>electrical</b>, enter:<p><tt>author=smith and title=electrical</tt>
-
-Please\ enter\ the\ field\ to\ search\ (e.g.\ <b>keywords</b>)\ and\ the\ keyword\ to\ search\ it\ for\ (e.g.\ <b>electrical</b>).=Please enter the field to search (e.g. <b>keywords</b>) and the keyword to search it for (e.g. <b>electrical</b>).
-
 Please\ enter\ the\ string's\ label=Please enter the string's label
 
 Please\ restart\ JabRef\ for\ preferences\ to\ take\ effect.=Please restart JabRef for preferences to take effect.
@@ -874,20 +865,12 @@ The\ label\ of\ the\ string\ cannot\ contain\ the\ '\#'\ character.=The label of
 
 The\ output\ option\ depends\ on\ a\ valid\ import\ option.=The output option depends on a valid import option.
 
-The\ regular\ expression\ <b>%0</b>\ is\ invalid\:=The regular expression <b>%0</b> is invalid:
-
 The\ search\ is\ case\ insensitive.=The search is case insensitive.
 
 The\ search\ is\ case\ sensitive.=The search is case sensitive.
 
 There\ are\ possible\ duplicates\ (marked\ with\ an\ icon)\ that\ haven't\ been\ resolved.\ Continue?=There are possible duplicates (marked with an icon) that haven't been resolved. Continue?
 
-This\ group\ contains\ entries\ based\ on\ manual\ assignment.\ Entries\ can\ be\ assigned\ to\ this\ group\ by\ selecting\ them\ then\ using\ either\ drag\ and\ drop\ or\ the\ context\ menu.\ Entries\ can\ be\ removed\ from\ this\ group\ by\ selecting\ them\ then\ using\ the\ context\ menu.=This group contains entries based on manual assignment. Entries can be assigned to this group by selecting them then using either drag and drop or the context menu. Entries can be removed from this group by selecting them then using the context menu.
-
-This\ group\ contains\ entries\ whose\ <b>%0</b>\ field\ contains\ the\ keyword\ <b>%1</b>=This group contains entries whose <b>%0</b> field contains the keyword <b>%1</b>
-
-This\ group\ contains\ entries\ whose\ <b>%0</b>\ field\ contains\ the\ regular\ expression\ <b>%1</b>=This group contains entries whose <b>%0</b> field contains the regular expression <b>%1</b>
-
 This\ operation\ requires\ all\ selected\ entries\ to\ have\ BibTeX\ keys\ defined.=This operation requires all selected entries to have BibTeX keys defined.
 
 This\ operation\ requires\ one\ or\ more\ entries\ to\ be\ selected.=This operation requires one or more entries to be selected.
@@ -1027,8 +1010,6 @@ Could\ not\ save,\ file\ locked\ by\ another\ JabRef\ instance.=Could not save,
 Metadata\ change=Metadata change
 The\ following\ metadata\ changed\:=The following metadata changed:
 
-Generate\ groups\ for\ author\ last\ names=Generate groups for author last names
-Generate\ groups\ from\ keywords\ in\ a\ BibTeX\ field=Generate groups from keywords in a BibTeX field
 Enforce\ legal\ characters\ in\ BibTeX\ keys=Enforce legal characters in BibTeX keys
 
 Unable\ to\ create\ backup=Unable to create backup
@@ -1222,7 +1203,7 @@ Not\ connected\ to\ any\ Writer\ document.\ Please\ make\ sure\ a\ document\ is\
 Removed\ all\ subgroups\ of\ group\ "%0".=Removed all subgroups of group "%0".
 To\ disable\ the\ memory\ stick\ mode\ rename\ or\ remove\ the\ jabref.xml\ file\ in\ the\ same\ folder\ as\ JabRef.=To disable the memory stick mode rename or remove the jabref.xml file in the same folder as JabRef.
 Unable\ to\ connect.\ One\ possible\ reason\ is\ that\ JabRef\ and\ OpenOffice/LibreOffice\ are\ not\ both\ running\ in\ either\ 32\ bit\ mode\ or\ 64\ bit\ mode.=Unable to connect. One possible reason is that JabRef and OpenOffice/LibreOffice are not both running in either 32 bit mode or 64 bit mode.
-Delimiter\ character(s)\:=Delimiter character(s):
+Delimiter(s)=Delimiter(s)
 When\ downloading\ files,\ or\ moving\ linked\ files\ to\ the\ file\ directory,\ prefer\ the\ BIB\ file\ location\ rather\ than\ the\ file\ directory\ set\ above=When downloading files, or moving linked files to the file directory, prefer the BIB file location rather than the file directory set above
 Your\ style\ file\ specifies\ the\ character\ format\ '%0',\ which\ is\ undefined\ in\ your\ current\ OpenOffice/LibreOffice\ document.=Your style file specifies the character format '%0', which is undefined in your current OpenOffice/LibreOffice document.
 Your\ style\ file\ specifies\ the\ paragraph\ format\ '%0',\ which\ is\ undefined\ in\ your\ current\ OpenOffice/LibreOffice\ document.=Your style file specifies the paragraph format '%0', which is undefined in your current OpenOffice/LibreOffice document.
@@ -1941,7 +1922,6 @@ Server\ Timezone\:=Server Timezone\:
 Remember\ Password=Remember Password
 Use\ SSL=Use SSL
 Move\ preprint\ information\ from\ 'URL'\ and\ 'journal'\ field\ to\ the\ 'eprint'\ field=Move preprint information from 'URL' and 'journal' field to the 'eprint' field
-Type=Type
 Customize\ Export\ Formats=Customize Export Formats
 Export\ name=Export name
 Main\ layout\ file\:=Main layout file\:
@@ -2104,8 +2084,6 @@ Dismiss=Dismiss
 Mark\ all\ changes\ as\ accepted=Mark all changes as accepted
 Unmark\ all\ changes=Unmark all changes
 
-Invalid\ regular\ expression\:=Invalid regular expression:
-
 Independent=Independent
 Intersection=Intersection
 Union=Union
@@ -2116,3 +2094,4 @@ Free\ search\ expression=Free search expression
 Specified\ keywords=Specified keywords
 Cited\ entries=Cited entries
 Search\ term\ is\ empty.=Search term is empty.
+Invalid\ regular\ expression.=Invalid regular expression.

From 84bece2a2a60c1f4d42816cb80bde92583a5336c Mon Sep 17 00:00:00 2001
From: Carl Christian Snethlage <cc.snethlage@gmail.com>
Date: Sun, 19 Jan 2020 00:07:27 +0100
Subject: [PATCH 5/9] Minor visual adjustments

---
 src/main/java/org/jabref/gui/Base.css         |  2 +-
 .../org/jabref/gui/groups/GroupDialog.fxml    | 26 ++++++++++++-------
 src/main/resources/l10n/JabRef_en.properties  |  2 +-
 3 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/src/main/java/org/jabref/gui/Base.css b/src/main/java/org/jabref/gui/Base.css
index 8392be71d72..c136404b276 100644
--- a/src/main/java/org/jabref/gui/Base.css
+++ b/src/main/java/org/jabref/gui/Base.css
@@ -311,7 +311,7 @@
 
 .button {
     -fx-background-color: transparent;
-    -fx-border-color: rgba(0, 0, 0, 0.23);
+    -fx-border-color: -fx-outer-border; /* rgba(0, 0, 0, 0.23); */
     -fx-border-width: 1px;
     -fx-border-radius: 4px;
     -fx-padding: 0.5em 1em 0.5em 1em;
diff --git a/src/main/java/org/jabref/gui/groups/GroupDialog.fxml b/src/main/java/org/jabref/gui/groups/GroupDialog.fxml
index 8b2b424ccf5..7fc0e3ffbf4 100644
--- a/src/main/java/org/jabref/gui/groups/GroupDialog.fxml
+++ b/src/main/java/org/jabref/gui/groups/GroupDialog.fxml
@@ -89,7 +89,7 @@
                             <CheckBox fx:id="keywordGroupRegex" text="Regular expression"/>
                         </HBox>
                     </VBox>
-                    <VBox visible="${searchRadioButton.selected}" spacing="4.0">
+                    <VBox visible="${searchRadioButton.selected}" spacing="10.0">
                         <VBox>
                             <Label text="%Search expression"/>
                             <TextField fx:id="searchGroupSearchTerm"/>
@@ -99,26 +99,34 @@
                             <CheckBox fx:id="searchGroupRegex" text="Regular expression"/>
                         </HBox>
                     </VBox>
-                    <VBox visible="${autoRadioButton.selected}" spacing="4.0">
+                    <VBox visible="${autoRadioButton.selected}" spacing="10.0">
                         <RadioButton fx:id="autoGroupKeywordsOption" toggleGroup="$autoGroupOptions"
                                      text="Generate groups from keywords in a BibTeX field"/>
                         <VBox spacing="10.0">
                             <padding>
                                 <Insets left="20.0"/>
                             </padding>
-                            <HBox spacing="4.0">
+                            <HBox spacing="10.0">
                                 <VBox HBox.hgrow="ALWAYS">
-                                    <Label text="%Field to group by:"/>
+                                    <Label text="%Field to group by"/>
                                     <TextField fx:id="autoGroupKeywordsField"
                                                disable="${!autoGroupKeywordsOption.selected}"/>
                                 </VBox>
                                 <VBox>
                                     <Label text="%Delimiter(s)"/>
                                     <HBox spacing="10.0">
-                                        <TextField fx:id="autoGroupKeywordsDeliminator" prefWidth="25.0"
-                                                   disable="${!autoGroupKeywordsOption.selected}"/>
-                                        <TextField fx:id="autoGroupKeywordsHierarchicalDeliminator" prefWidth="25.0"
-                                                   disable="${!autoGroupKeywordsOption.selected}"/>
+                                        <TextField fx:id="autoGroupKeywordsDeliminator" prefWidth="30.0"
+                                                   disable="${!autoGroupKeywordsOption.selected}">
+                                            <tooltip>
+                                                <Tooltip text="%Keyword delimiter"/>
+                                            </tooltip>
+                                        </TextField>
+                                        <TextField fx:id="autoGroupKeywordsHierarchicalDeliminator" prefWidth="30.0"
+                                                   disable="${!autoGroupKeywordsOption.selected}">
+                                            <tooltip>
+                                                <Tooltip text="%Hierarchical keyword delimiter"/>
+                                            </tooltip>
+                                        </TextField>
                                     </HBox>
                                 </VBox>
                             </HBox>
@@ -129,7 +137,7 @@
                             <padding>
                                 <Insets left="20.0"/>
                             </padding>
-                            <Label text="%Field to group by:"/>
+                            <Label text="%Field to group by"/>
                             <TextField fx:id="autoGroupPersonsField" disable="${!autoGroupPersonsOption.selected}"/>
                         </VBox>
                     </VBox>
diff --git a/src/main/resources/l10n/JabRef_en.properties b/src/main/resources/l10n/JabRef_en.properties
index 8fa2298153b..e5d81ddaab3 100644
--- a/src/main/resources/l10n/JabRef_en.properties
+++ b/src/main/resources/l10n/JabRef_en.properties
@@ -343,7 +343,7 @@ field=field
 Field\ name=Field name
 Field\ names\ are\ not\ allowed\ to\ contain\ white\ space\ or\ the\ following\ characters=Field names are not allowed to contain white space or the following characters
 
-Field\ to\ group\ by\:=Field to group by:
+Field\ to\ group\ by=Field to group by
 
 File=File
 

From 3579f6e71acd757b12acb691c30fa29b2528e136 Mon Sep 17 00:00:00 2001
From: Carl Christian Snethlage <cc.snethlage@gmail.com>
Date: Sun, 19 Jan 2020 00:18:43 +0100
Subject: [PATCH 6/9] forgotten l10n resources

---
 src/main/resources/l10n/JabRef_en.properties | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/main/resources/l10n/JabRef_en.properties b/src/main/resources/l10n/JabRef_en.properties
index e5d81ddaab3..4d0d676e0d4 100644
--- a/src/main/resources/l10n/JabRef_en.properties
+++ b/src/main/resources/l10n/JabRef_en.properties
@@ -2095,3 +2095,5 @@ Specified\ keywords=Specified keywords
 Cited\ entries=Cited entries
 Search\ term\ is\ empty.=Search term is empty.
 Invalid\ regular\ expression.=Invalid regular expression.
+Keyword\ delimiter=Keyword delimiter
+Hierarchical\ keyword\ delimiter=Hierarchical keyword delimiter

From 64c3c6e9a91713fd7198a12376bc98bbafa080a0 Mon Sep 17 00:00:00 2001
From: Carl Christian Snethlage <cc.snethlage@gmail.com>
Date: Tue, 21 Jan 2020 12:12:41 +0100
Subject: [PATCH 7/9] Minor refactoring, and changed comment

---
 src/main/java/org/jabref/gui/groups/GroupDialogViewModel.java   | 2 +-
 .../java/org/jabref/gui/maintable/MainTableColumnFactory.java   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/main/java/org/jabref/gui/groups/GroupDialogViewModel.java b/src/main/java/org/jabref/gui/groups/GroupDialogViewModel.java
index 4d3101be4d6..a4c36108322 100644
--- a/src/main/java/org/jabref/gui/groups/GroupDialogViewModel.java
+++ b/src/main/java/org/jabref/gui/groups/GroupDialogViewModel.java
@@ -113,7 +113,7 @@ public GroupDialogViewModel(DialogService dialogService, BasePanel basePanel, Ja
         this.basePanel = basePanel;
         this.editedGroup = editedGroup;
 
-        this.keywordDelimiter = Globals.prefs.getKeywordDelimiter();
+        this.keywordDelimiter = preferences.getKeywordDelimiter();
 
         setupValidation();
         setValues();
diff --git a/src/main/java/org/jabref/gui/maintable/MainTableColumnFactory.java b/src/main/java/org/jabref/gui/maintable/MainTableColumnFactory.java
index d927845200a..bde67b260aa 100644
--- a/src/main/java/org/jabref/gui/maintable/MainTableColumnFactory.java
+++ b/src/main/java/org/jabref/gui/maintable/MainTableColumnFactory.java
@@ -131,7 +131,7 @@ private void setExactWidth(TableColumn<?, ?> column, double width) {
     }
 
     /**
-     * Creates a text column to display any standard field.
+     * Creates a column with a continous number
      */
     private TableColumn<BibEntryTableViewModel, String> createIndexColumn(MainTableColumnModel columnModel) {
         TableColumn<BibEntryTableViewModel, String> column = new MainTableColumn<>(columnModel);

From a7db26ee64b178e359d69be7bc676b709b0d46b8 Mon Sep 17 00:00:00 2001
From: Carl Christian Snethlage <cc.snethlage@gmail.com>
Date: Sat, 25 Jan 2020 21:40:37 +0100
Subject: [PATCH 8/9] Refactored constructors, PreferencesService and some
 minor improvements.

---
 .../org/jabref/gui/groups/GroupDialog.fxml    |  21 ++--
 .../jabref/gui/groups/GroupDialogView.java    |  63 +++-------
 .../gui/groups/GroupDialogViewModel.java      |  36 +++---
 .../org/jabref/gui/groups/GroupTreeView.java  |   5 +-
 .../jabref/gui/groups/GroupTreeViewModel.java | 119 ++++++++++--------
 5 files changed, 119 insertions(+), 125 deletions(-)

diff --git a/src/main/java/org/jabref/gui/groups/GroupDialog.fxml b/src/main/java/org/jabref/gui/groups/GroupDialog.fxml
index 7fc0e3ffbf4..797af93a1ad 100644
--- a/src/main/java/org/jabref/gui/groups/GroupDialog.fxml
+++ b/src/main/java/org/jabref/gui/groups/GroupDialog.fxml
@@ -39,9 +39,20 @@
                     <ComboBox fx:id="hierarchicalContextCombo" minWidth="130.0" maxWidth="130.0" prefWidth="130.0"/>
                 </VBox>
             </HBox>
+            <HBox alignment="BOTTOM_LEFT">
+                <Label text="%Collect by" styleClass="sectionHeader"/>
+                <HBox HBox.hgrow="ALWAYS"/>
+                <Button styleClass="icon-button,narrow" onAction="#openHelp">
+                    <graphic>
+                        <JabRefIconView glyph="HELP"/>
+                    </graphic>
+                    <tooltip>
+                        <Tooltip text="%Open Help page"/>
+                    </tooltip>
+                </Button>
+            </HBox>
             <HBox>
                 <VBox spacing="10.0">
-                    <Label text="%Collect by"/>
                     <RadioButton fx:id="explicitRadioButton" toggleGroup="$type" wrapText="true"
                                  text="%Explicit selection">
                         <tooltip>
@@ -149,14 +160,6 @@
                         </HBox>
                     </VBox>
                 </StackPane>
-                <Button styleClass="icon-button,narrow" onAction="#openHelp">
-                    <graphic>
-                        <JabRefIconView glyph="HELP"/>
-                    </graphic>
-                    <tooltip>
-                        <Tooltip text="%Open Help page"/>
-                    </tooltip>
-                </Button>
             </HBox>
         </VBox>
     </content>
diff --git a/src/main/java/org/jabref/gui/groups/GroupDialogView.java b/src/main/java/org/jabref/gui/groups/GroupDialogView.java
index 57643a7ab68..67b7122c553 100644
--- a/src/main/java/org/jabref/gui/groups/GroupDialogView.java
+++ b/src/main/java/org/jabref/gui/groups/GroupDialogView.java
@@ -1,5 +1,7 @@
 package org.jabref.gui.groups;
 
+import java.util.EnumMap;
+
 import javafx.application.Platform;
 import javafx.fxml.FXML;
 import javafx.scene.control.ButtonType;
@@ -9,17 +11,15 @@
 import javafx.scene.control.RadioButton;
 import javafx.scene.control.TextField;
 
-import org.jabref.Globals;
-import org.jabref.JabRefGUI;
-import org.jabref.gui.BasePanel;
 import org.jabref.gui.DialogService;
 import org.jabref.gui.util.BaseDialog;
 import org.jabref.gui.util.IconValidationDecorator;
 import org.jabref.gui.util.ViewModelListCellFactory;
 import org.jabref.logic.l10n.Localization;
+import org.jabref.model.database.BibDatabaseContext;
 import org.jabref.model.groups.AbstractGroup;
 import org.jabref.model.groups.GroupHierarchyType;
-import org.jabref.preferences.JabRefPreferences;
+import org.jabref.preferences.PreferencesService;
 
 import com.airhacks.afterburner.views.ViewLoader;
 import de.saxsys.mvvmfx.utils.validation.visualization.ControlsFxVisualizer;
@@ -59,11 +59,14 @@ public class GroupDialogView extends BaseDialog<AbstractGroup> {
 
     @FXML private TextField texGroupFilePath;
 
+    private final EnumMap<GroupHierarchyType,String> hierarchyText = new EnumMap<>(GroupHierarchyType.class);
+    private final EnumMap<GroupHierarchyType,String> hierarchyToolTip = new EnumMap<>(GroupHierarchyType.class);
+
     private final ControlsFxVisualizer validationVisualizer = new ControlsFxVisualizer();
     private final GroupDialogViewModel viewModel;
 
-    public GroupDialogView(DialogService dialogService, BasePanel basePanel, JabRefPreferences prefs, AbstractGroup editedGroup) {
-        viewModel = new GroupDialogViewModel(dialogService, basePanel, prefs, editedGroup);
+    public GroupDialogView(DialogService dialogService, BibDatabaseContext currentDatabase, PreferencesService preferencesService, AbstractGroup editedGroup) {
+        viewModel = new GroupDialogViewModel(dialogService, currentDatabase, preferencesService, editedGroup);
 
         ViewLoader.view(this)
                   .load()
@@ -76,54 +79,26 @@ public GroupDialogView(DialogService dialogService, BasePanel basePanel, JabRefP
         }
 
         setResultConverter(viewModel::resultConverter);
-
         getDialogPane().getButtonTypes().setAll(ButtonType.OK, ButtonType.CANCEL);
-
-        getDialogPane().getScene().getWindow().sizeToScene();
-    }
-
-    public GroupDialogView(DialogService dialogService, AbstractGroup editedGroup) {
-        this(dialogService, JabRefGUI.getMainFrame().getCurrentBasePanel(), Globals.prefs, editedGroup);
-    }
-
-    public GroupDialogView(DialogService dialogService) {
-        this(dialogService, JabRefGUI.getMainFrame().getCurrentBasePanel(), Globals.prefs, null);
-    }
-
-    private String getHierarchyDisplayText(GroupHierarchyType type) {
-        switch (type) {
-            case INCLUDING:
-                return Localization.lang("Union");
-            case REFINING:
-                return Localization.lang("Intersection");
-            default:
-            case INDEPENDENT:
-                return Localization.lang("Independent");
-        }
-    }
-
-    private String getHierarchyToolTip(GroupHierarchyType type) {
-        switch (type) {
-            case INCLUDING:
-                return Localization.lang("Include subgroups: When selected, view entries contained in this group or its subgroups");
-            case REFINING:
-                return Localization.lang("Refine supergroup: When selected, view entries contained in both this group and its supergroup");
-            default:
-            case INDEPENDENT:
-                return Localization.lang("Independent group: When selected, view only this group's entries");
-        }
     }
 
     @FXML
     public void initialize() {
+        hierarchyText.put(GroupHierarchyType.INCLUDING, Localization.lang("Union"));
+        hierarchyToolTip.put(GroupHierarchyType.INCLUDING, Localization.lang("Include subgroups: When selected, view entries contained in this group or its subgroups"));
+        hierarchyText.put(GroupHierarchyType.REFINING, Localization.lang("Intersection"));
+        hierarchyToolTip.put(GroupHierarchyType.REFINING, Localization.lang("Refine supergroup: When selected, view entries contained in both this group and its supergroup"));
+        hierarchyText.put(GroupHierarchyType.INDEPENDENT, Localization.lang("Independent"));
+        hierarchyToolTip.put(GroupHierarchyType.INDEPENDENT, Localization.lang("Independent group: When selected, view only this group's entries"));
+
         nameField.textProperty().bindBidirectional(viewModel.nameProperty());
         descriptionField.textProperty().bindBidirectional(viewModel.descriptionProperty());
         iconField.textProperty().bindBidirectional(viewModel.iconProperty());
         colorField.valueProperty().bindBidirectional(viewModel.colorFieldProperty());
         hierarchicalContextCombo.itemsProperty().bind(viewModel.groupHierarchyListProperty());
         new ViewModelListCellFactory<GroupHierarchyType>()
-                .withText(this::getHierarchyDisplayText)
-                .withStringTooltip(this::getHierarchyToolTip)
+                .withText(hierarchyText::get)
+                .withStringTooltip(hierarchyToolTip::get)
                 .install(hierarchicalContextCombo);
         hierarchicalContextCombo.valueProperty().bindBidirectional(viewModel.groupHierarchySelectedProperty());
 
@@ -162,7 +137,7 @@ public void initialize() {
             validationVisualizer.initVisualization(viewModel.keywordSearchTermEmptyValidationStatus(), keywordGroupSearchTerm);
         });
 
-        // Binding to the validProperty throws an NPE, so we have to work around this issue
+        // Binding to the button throws a NPE, since it doesn't exist yet. Working around.
         viewModel.validationStatus().validProperty().addListener((obs, oldValue, newValue) -> {
             if (newValue) {
                 getDialogPane().lookupButton(ButtonType.OK).setDisable(false);
diff --git a/src/main/java/org/jabref/gui/groups/GroupDialogViewModel.java b/src/main/java/org/jabref/gui/groups/GroupDialogViewModel.java
index a4c36108322..47a2c88f52f 100644
--- a/src/main/java/org/jabref/gui/groups/GroupDialogViewModel.java
+++ b/src/main/java/org/jabref/gui/groups/GroupDialogViewModel.java
@@ -22,7 +22,6 @@
 import javafx.scene.paint.Color;
 
 import org.jabref.Globals;
-import org.jabref.gui.BasePanel;
 import org.jabref.gui.DialogService;
 import org.jabref.gui.help.HelpAction;
 import org.jabref.gui.icon.IconTheme;
@@ -33,6 +32,7 @@
 import org.jabref.logic.util.StandardFileType;
 import org.jabref.logic.util.io.FileUtil;
 import org.jabref.model.database.BibDatabase;
+import org.jabref.model.database.BibDatabaseContext;
 import org.jabref.model.entry.field.FieldFactory;
 import org.jabref.model.groups.AbstractGroup;
 import org.jabref.model.groups.AutomaticGroup;
@@ -47,7 +47,7 @@
 import org.jabref.model.groups.WordKeywordGroup;
 import org.jabref.model.metadata.MetaData;
 import org.jabref.model.strings.StringUtil;
-import org.jabref.preferences.JabRefPreferences;
+import org.jabref.preferences.PreferencesService;
 
 import de.saxsys.mvvmfx.utils.validation.CompositeValidator;
 import de.saxsys.mvvmfx.utils.validation.FunctionBasedValidator;
@@ -101,20 +101,16 @@ public class GroupDialogViewModel {
     private CompositeValidator validator = new CompositeValidator();
 
     private final DialogService dialogService;
-    private final JabRefPreferences preferences;
-    private final BasePanel basePanel;
+    private final PreferencesService preferencesService;
+    private final BibDatabaseContext currentDatabase;
     private final AbstractGroup editedGroup;
 
-    private final Character keywordDelimiter;
-
-    public GroupDialogViewModel(DialogService dialogService, BasePanel basePanel, JabRefPreferences preferences, AbstractGroup editedGroup) {
+    public GroupDialogViewModel(DialogService dialogService, BibDatabaseContext currentDatabase, PreferencesService preferencesService, AbstractGroup editedGroup) {
         this.dialogService = dialogService;
-        this.preferences = preferences;
-        this.basePanel = basePanel;
+        this.preferencesService = preferencesService;
+        this.currentDatabase = currentDatabase;
         this.editedGroup = editedGroup;
 
-        this.keywordDelimiter = preferences.getKeywordDelimiter();
-
         setupValidation();
         setValues();
     }
@@ -127,17 +123,17 @@ private void setupValidation() {
 
         nameContainsDelimiterValidator = new FunctionBasedValidator<>(
                 nameProperty,
-                name -> !name.contains(Character.toString(keywordDelimiter)),
+                name -> !name.contains(Character.toString(preferencesService.getKeywordDelimiter())),
                 ValidationMessage.warning(
                         Localization.lang(
                                 "The group name contains the keyword separator \"%0\" and thus probably does not work as expected.",
-                                Character.toString(keywordDelimiter)
+                                Character.toString(preferencesService.getKeywordDelimiter())
                         )));
 
         sameNameValidator = new FunctionBasedValidator<>(
                 nameProperty,
                 name -> {
-                    Optional<GroupTreeNode> rootGroup = basePanel.getBibDatabaseContext().getMetaData().getGroups();
+                    Optional<GroupTreeNode> rootGroup = currentDatabase.getMetaData().getGroups();
                     if (rootGroup.isPresent()) {
                         int groupsWithSameName = rootGroup.get().findChildrenSatisfying(group -> group.getName().equals(name)).size();
                         if ((editedGroup == null) && (groupsWithSameName > 0)) {
@@ -250,7 +246,7 @@ public AbstractGroup resultConverter(ButtonType button) {
                     resultingGroup = new ExplicitGroup(
                             groupName,
                             groupHierarchySelectedProperty.getValue(),
-                            keywordDelimiter);
+                            preferencesService.getKeywordDelimiter());
                 } else if (typeKeywordsProperty.getValue()) {
                     if (keywordGroupRegexProperty.getValue()) {
                         resultingGroup = new RegexKeywordGroup(
@@ -266,7 +262,7 @@ public AbstractGroup resultConverter(ButtonType button) {
                                 FieldFactory.parseField(keywordGroupSearchFieldProperty.getValue().trim()),
                                 keywordGroupSearchTermProperty.getValue().trim(),
                                 keywordGroupCaseSensitiveProperty.getValue(),
-                                keywordDelimiter,
+                                preferencesService.getKeywordDelimiter(),
                                 false);
                     }
                 } else if (typeSearchProperty.getValue()) {
@@ -297,7 +293,7 @@ public AbstractGroup resultConverter(ButtonType button) {
                             Paths.get(texGroupFilePathProperty.getValue().trim()),
                             new DefaultAuxParser(new BibDatabase()),
                             Globals.getFileUpdateMonitor(),
-                            basePanel.getBibDatabaseContext().getMetaData());
+                            currentDatabase.getMetaData());
                 }
 
                 if (resultingGroup != null) {
@@ -382,7 +378,7 @@ public void texGroupBrowse() {
         FileDialogConfiguration fileDialogConfiguration = new FileDialogConfiguration.Builder()
                 .addExtensionFilter(StandardFileType.AUX)
                 .withDefaultExtension(StandardFileType.AUX)
-                .withInitialDirectory(Globals.prefs.get(JabRefPreferences.WORKING_DIRECTORY)).build();
+                .withInitialDirectory(preferencesService.getWorkingDir()).build();
         dialogService.showFileOpenDialog(fileDialogConfiguration)
                      .ifPresent(file -> texGroupFilePathProperty.setValue(
                              FileUtil.relativize(file.toAbsolutePath(), getFileDirectoriesAsPaths()).toString()
@@ -395,8 +391,8 @@ public void openHelpPage() {
 
     private List<Path> getFileDirectoriesAsPaths() {
         List<Path> fileDirs = new ArrayList<>();
-        MetaData metaData = basePanel.getBibDatabaseContext().getMetaData();
-        metaData.getLaTexFileDirectory(preferences.getFilePreferences().getUser()).ifPresent(fileDirs::add);
+        MetaData metaData = currentDatabase.getMetaData();
+        metaData.getLaTexFileDirectory(preferencesService.getFilePreferences().getUser()).ifPresent(fileDirs::add);
 
         return fileDirs;
     }
diff --git a/src/main/java/org/jabref/gui/groups/GroupTreeView.java b/src/main/java/org/jabref/gui/groups/GroupTreeView.java
index b410e6be80d..aad18e6af6d 100644
--- a/src/main/java/org/jabref/gui/groups/GroupTreeView.java
+++ b/src/main/java/org/jabref/gui/groups/GroupTreeView.java
@@ -45,6 +45,7 @@
 import org.jabref.logic.l10n.Localization;
 import org.jabref.model.entry.BibEntry;
 import org.jabref.model.groups.AllEntriesGroup;
+import org.jabref.preferences.PreferencesService;
 
 import org.controlsfx.control.textfield.CustomTextField;
 import org.controlsfx.control.textfield.TextFields;
@@ -67,6 +68,8 @@ public class GroupTreeView {
     @Inject private StateManager stateManager;
     @Inject private DialogService dialogService;
     @Inject private TaskExecutor taskExecutor;
+    @Inject private PreferencesService preferencesService;
+
     private GroupTreeViewModel viewModel;
     private CustomLocalDragboard localDragboard;
 
@@ -75,7 +78,7 @@ public class GroupTreeView {
     @FXML
     public void initialize() {
         this.localDragboard = GUIGlobals.localDragboard;
-        viewModel = new GroupTreeViewModel(stateManager, dialogService, taskExecutor, localDragboard);
+        viewModel = new GroupTreeViewModel(stateManager, dialogService, preferencesService, taskExecutor, localDragboard);
 
         // Set-up groups tree
         groupTree.getSelectionModel().setSelectionMode(SelectionMode.MULTIPLE);
diff --git a/src/main/java/org/jabref/gui/groups/GroupTreeViewModel.java b/src/main/java/org/jabref/gui/groups/GroupTreeViewModel.java
index 85b710f8539..d0b77597aad 100644
--- a/src/main/java/org/jabref/gui/groups/GroupTreeViewModel.java
+++ b/src/main/java/org/jabref/gui/groups/GroupTreeViewModel.java
@@ -29,6 +29,7 @@
 import org.jabref.model.groups.ExplicitGroup;
 import org.jabref.model.groups.GroupTreeNode;
 import org.jabref.model.metadata.MetaData;
+import org.jabref.preferences.PreferencesService;
 
 import org.fxmisc.easybind.EasyBind;
 
@@ -38,6 +39,7 @@ public class GroupTreeViewModel extends AbstractViewModel {
     private final ListProperty<GroupNodeViewModel> selectedGroups = new SimpleListProperty<>(FXCollections.observableArrayList());
     private final StateManager stateManager;
     private final DialogService dialogService;
+    private final PreferencesService preferences;
     private final TaskExecutor taskExecutor;
     private final CustomLocalDragboard localDragboard;
     private final ObjectProperty<Predicate<GroupNodeViewModel>> filterPredicate = new SimpleObjectProperty<>();
@@ -47,9 +49,10 @@ public class GroupTreeViewModel extends AbstractViewModel {
             .compareToIgnoreCase(v2.getName());
     private Optional<BibDatabaseContext> currentDatabase;
 
-    public GroupTreeViewModel(StateManager stateManager, DialogService dialogService, TaskExecutor taskExecutor, CustomLocalDragboard localDragboard) {
+    public GroupTreeViewModel(StateManager stateManager, DialogService dialogService, PreferencesService preferencesService, TaskExecutor taskExecutor, CustomLocalDragboard localDragboard) {
         this.stateManager = Objects.requireNonNull(stateManager);
         this.dialogService = Objects.requireNonNull(dialogService);
+        this.preferences = Objects.requireNonNull(preferencesService);
         this.taskExecutor = Objects.requireNonNull(taskExecutor);
         this.localDragboard = Objects.requireNonNull(localDragboard);
 
@@ -142,69 +145,83 @@ private void onActiveDatabaseChanged(Optional<BibDatabaseContext> newDatabase) {
      * Opens "New Group Dialog" and add the resulting group to the specified group
      */
     public void addNewSubgroup(GroupNodeViewModel parent) {
-        Optional<AbstractGroup> newGroup = dialogService.showCustomDialogAndWait(new GroupDialogView(dialogService));
-        newGroup.ifPresent(group -> {
-            parent.addSubgroup(group);
+        currentDatabase.ifPresent(database -> {
+            Optional<AbstractGroup> newGroup = dialogService.showCustomDialogAndWait(new GroupDialogView(
+                    dialogService,
+                    database,
+                    preferences,
+                    null));
 
-            // TODO: Add undo
-            //UndoableAddOrRemoveGroup undo = new UndoableAddOrRemoveGroup(parent, new GroupTreeNodeViewModel(newGroupNode), UndoableAddOrRemoveGroup.ADD_NODE);
-            //panel.getUndoManager().addEdit(undo);
+            newGroup.ifPresent(group -> {
+                parent.addSubgroup(group);
 
-            // TODO: Expand parent to make new group visible
-            //parent.expand();
+                // TODO: Add undo
+                //UndoableAddOrRemoveGroup undo = new UndoableAddOrRemoveGroup(parent, new GroupTreeNodeViewModel(newGroupNode), UndoableAddOrRemoveGroup.ADD_NODE);
+                //panel.getUndoManager().addEdit(undo);
 
-            dialogService.notify(Localization.lang("Added group \"%0\".", group.getName()));
-            writeGroupChangesToMetaData();
+                // TODO: Expand parent to make new group visible
+                //parent.expand();
+
+                dialogService.notify(Localization.lang("Added group \"%0\".", group.getName()));
+                writeGroupChangesToMetaData();
+            });
         });
     }
 
     private void writeGroupChangesToMetaData() {
-        currentDatabase.get().getMetaData().setGroups(rootGroup.get().getGroupNode());
+        currentDatabase.ifPresent(database -> database.getMetaData().setGroups(rootGroup.get().getGroupNode()));
     }
 
     /**
      * Opens "Edit Group Dialog" and changes the given group to the edited one.
      */
     public void editGroup(GroupNodeViewModel oldGroup) {
-        Optional<AbstractGroup> newGroup = dialogService
-                .showCustomDialogAndWait(new GroupDialogView(dialogService, oldGroup.getGroupNode().getGroup()));
-        newGroup.ifPresent(group -> {
-            // TODO: Keep assignments
-            boolean keepPreviousAssignments = dialogService.showConfirmationDialogAndWait(
-                    Localization.lang("Change of Grouping Method"),
-                    Localization.lang("Assign the original group's entries to this group?"));
-            //        WarnAssignmentSideEffects.warnAssignmentSideEffects(newGroup, panel.frame());
-            boolean removePreviousAssignments = (oldGroup.getGroupNode().getGroup() instanceof ExplicitGroup)
-                    && (group instanceof ExplicitGroup);
-
-            oldGroup.getGroupNode().setGroup(
-                    group,
-                    keepPreviousAssignments,
-                    removePreviousAssignments,
-                    stateManager.getEntriesInCurrentDatabase());
-
-            // TODO: Add undo
-            // Store undo information.
-            // AbstractUndoableEdit undoAddPreviousEntries = null;
-            // UndoableModifyGroup undo = new UndoableModifyGroup(GroupSelector.this, groupsRoot, node, newGroup);
-            // if (undoAddPreviousEntries == null) {
-            //    panel.getUndoManager().addEdit(undo);
-            //} else {
-            //    NamedCompound nc = new NamedCompound("Modify Group");
-            //    nc.addEdit(undo);
-            //    nc.addEdit(undoAddPreviousEntries);
-            //    nc.end();/
-            //      panel.getUndoManager().addEdit(nc);
-            //}
-            //if (!addChange.isEmpty()) {
-            //    undoAddPreviousEntries = UndoableChangeEntriesOfGroup.getUndoableEdit(null, addChange);
-            //}
-
-            dialogService.notify(Localization.lang("Modified group \"%0\".", group.getName()));
-            writeGroupChangesToMetaData();
-
-            // This is ugly but we have no proper update mechanism in place to propagate the changes, so redraw everything
-            refresh();
+        currentDatabase.ifPresent(database -> {
+            Optional<AbstractGroup> newGroup = dialogService.showCustomDialogAndWait(new GroupDialogView(
+                    dialogService,
+                    database,
+                    preferences,
+                    oldGroup.getGroupNode().getGroup()));
+
+            newGroup.ifPresent(group -> {
+                // TODO: Keep assignments
+                boolean keepPreviousAssignments = dialogService.showConfirmationDialogAndWait(
+                        Localization.lang("Change of Grouping Method"),
+                        Localization.lang("Assign the original group's entries to this group?"));
+                //        WarnAssignmentSideEffects.warnAssignmentSideEffects(newGroup, panel.frame());
+                boolean removePreviousAssignments = (oldGroup.getGroupNode().getGroup() instanceof ExplicitGroup)
+                        && (group instanceof ExplicitGroup);
+
+                oldGroup.getGroupNode().setGroup(
+                        group,
+                        keepPreviousAssignments,
+                        removePreviousAssignments,
+                        database.getEntries());
+                        // stateManager.getEntriesInCurrentDatabase());
+
+                // TODO: Add undo
+                // Store undo information.
+                // AbstractUndoableEdit undoAddPreviousEntries = null;
+                // UndoableModifyGroup undo = new UndoableModifyGroup(GroupSelector.this, groupsRoot, node, newGroup);
+                // if (undoAddPreviousEntries == null) {
+                //    panel.getUndoManager().addEdit(undo);
+                //} else {
+                //    NamedCompound nc = new NamedCompound("Modify Group");
+                //    nc.addEdit(undo);
+                //    nc.addEdit(undoAddPreviousEntries);
+                //    nc.end();/
+                //      panel.getUndoManager().addEdit(nc);
+                //}
+                //if (!addChange.isEmpty()) {
+                //    undoAddPreviousEntries = UndoableChangeEntriesOfGroup.getUndoableEdit(null, addChange);
+                //}
+
+                dialogService.notify(Localization.lang("Modified group \"%0\".", group.getName()));
+                writeGroupChangesToMetaData();
+
+                // This is ugly but we have no proper update mechanism in place to propagate the changes, so redraw everything
+                refresh();
+            });
         });
     }
 

From 584abaca4f72a11dd02f07cbdc3312b92e7dd661 Mon Sep 17 00:00:00 2001
From: Carl Christian Snethlage <cc.snethlage@gmail.com>
Date: Sat, 25 Jan 2020 21:56:27 +0100
Subject: [PATCH 9/9] Fixed Test

---
 .../java/org/jabref/gui/groups/GroupTreeViewModelTest.java     | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/test/java/org/jabref/gui/groups/GroupTreeViewModelTest.java b/src/test/java/org/jabref/gui/groups/GroupTreeViewModelTest.java
index 6e90070a69b..40d37af02b4 100644
--- a/src/test/java/org/jabref/gui/groups/GroupTreeViewModelTest.java
+++ b/src/test/java/org/jabref/gui/groups/GroupTreeViewModelTest.java
@@ -15,6 +15,7 @@
 import org.jabref.model.groups.ExplicitGroup;
 import org.jabref.model.groups.GroupHierarchyType;
 import org.jabref.model.groups.WordKeywordGroup;
+import org.jabref.preferences.PreferencesService;
 
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -34,7 +35,7 @@ public void setUp() throws Exception {
         stateManager = new StateManager();
         stateManager.activeDatabaseProperty().setValue(Optional.of(databaseContext));
         taskExecutor = new CurrentThreadTaskExecutor();
-        groupTree = new GroupTreeViewModel(stateManager, mock(DialogService.class), taskExecutor, new CustomLocalDragboard());
+        groupTree = new GroupTreeViewModel(stateManager, mock(DialogService.class), mock(PreferencesService.class), taskExecutor, new CustomLocalDragboard());
     }
 
     @Test