Fix custom theme styles not applied to the entry preview (#7071)

* Fix custom theme styles not applied to the entry preview

Make comment more precise

* cbheckstyle

* Update CHANGELOG.md

CHANGELOG.md

@@ -63,8 +63,9 @@ inserting new citations in a OpenOffic/LibreOffice document. [#6957](https://git
 - We fixed an issue where identity column header had incorrect foreground color in the Dark theme. [#6796](https://github.com/JabRef/jabref/issues/6796)
 - We fixed an issue where the RIS exporter added extra blank lines.[#7007](https://github.com/JabRef/jabref/pull/7007/files)
 - We fixed an issue where clicking on Collapse All button in the Search for Unlinked Local Files expanded the directory structure erroneously [#6848](https://github.com/JabRef/jabref/issues/6848)
-- We fixed an issue, when pulling changes from shared database via shortcut caused creation a new new tech report [6867](https://github.com/JabRef/jabref/issues/6867)
+- We fixed an issue, when pulling changes from shared database via shortcut caused creation of a new tech report [6867](https://github.com/JabRef/jabref/issues/6867)
 - We fixed an issue where the JabRef GUI does not highlight the "All entries" group on start-up [#6691](https://github.com/JabRef/jabref/issues/6691)
+- We fixed an issue where a custom dark theme was not applied to the entry preview tab [7068](https://github.com/JabRef/jabref/issues/7068)
 
 ### Removed
 

src/main/java/org/jabref/gui/preview/PreviewViewer.java

@@ -1,5 +1,6 @@
 package org.jabref.gui.preview;
 
+import java.net.MalformedURLException;
 import java.net.URL;
 import java.util.Base64;
 import java.util.Objects;
@@ -119,12 +120,19 @@ public PreviewViewer(BibDatabaseContext database, DialogService dialogService, S
  public void setTheme(Theme theme) {
  if (theme.getType() == Theme.Type.DARK) {
  // We need to load the css file manually, due to a bug in the jdk
- // TODO: Remove this workaround as soon as https://github.com/openjdk/jfx/pull/22 is merged
+ // https://bugs.openjdk.java.net/browse/JDK-8240969
+ // TODO: Remove this workaround as soon as openjfx 16 is released
  URL url = JabRefFrame.class.getResource(theme.getPath().getFileName().toString());
  String dataUrl = "data:text/css;charset=utf-8;base64," +
  Base64.getEncoder().encodeToString(StringUtil.getResourceFileAsString(url).getBytes());
 
  previewView.getEngine().setUserStyleSheetLocation(dataUrl);
+ } else if (theme.getType() != Theme.Type.LIGHT) {
+ try {
+ previewView.getEngine().setUserStyleSheetLocation(theme.getPath().toUri().toURL().toExternalForm());
+ } catch (MalformedURLException ex) {
+ LOGGER.error("Cannot set custom theme, invalid url", ex);
+ }
  }
  }
 
@@ -171,7 +179,7 @@ public void setEntry(BibEntry newEntry) {
  }
 
  private void update() {
- if (entry.isEmpty() || layout == null) {
+ if (entry.isEmpty() || (layout == null)) {
  // Nothing to do
  return;
  }