Switch colors of search icon for the two search modes

CHANGELOG.md

@@ -55,6 +55,7 @@ The new default removes the linked file from the entry instead of deleting the f
 - We fixed an issue where linked files would be deleted from bibliography entries despite choosing the "Cancel" option in the dialog menu.
 - We fixed the name of the group editing window to "Add group" instead of "Edit Group" when adding a new group. [koppor#277](https://github.com/koppor/jabref/issues/277)
 - We fixed an issue where the "Copy linked files" dialog produced an error when the entry had no file [#3818](https://github.com/JabRef/jabref/issues/3818)
+- We fixed the coloring of the search box icon in case a user switches to advanced search mode [#3870](https://github.com/JabRef/jabref/issues/3870)
 
 ### Removed
 - We removed the [Look and Feels from JGoodies](http://www.jgoodies.com/freeware/libraries/looks/), because the open source version is not compatible with Java 9.

src/main/java/org/jabref/gui/search/GlobalSearchBar.java

@@ -397,9 +397,9 @@ public void updateResults(int matched, TextFlow description, boolean grammarBase
             searchField.pseudoClassStateChanged(CLASS_RESULTS_FOUND, true);
         }
         if (grammarBasedSearch) {
-            searchIcon.setIcon(IconTheme.JabRefIcon.ADVANCED_SEARCH.getIcon());
-        } else {
             searchIcon.setIcon(IconTheme.JabRefIcon.SEARCH.getIcon());
+        } else {
+            searchIcon.setIcon(IconTheme.JabRefIcon.ADVANCED_SEARCH.getIcon());
         }
         Tooltip tooltip = new Tooltip();
         tooltip.setContentDisplay(ContentDisplay.GRAPHIC_ONLY);