Enable/Disable the undo and redo toolbar/menu buttons correctly

CHANGELOG.md

@@ -45,6 +45,7 @@ Note that this project **does not** adhere to [Semantic Versioning](https://semv
 - The browse button for a Custom theme now opens in the directory of the current used CSS file. [#11597](https://github.com/JabRef/jabref/pull/11597)
 - The browse button for a Custom exporter now opens in the directory of the current used exporter file. [#11717](https://github.com/JabRef/jabref/pull/11717)
 - We improved the display of long messages in the integrity check dialog. [#11619](https://github.com/JabRef/jabref/pull/11619)
+- We improved the undo/redo buttons in the main toolbar and main menu to be disabled when there is nothing to undo/redo. [#8807](https://github.com/JabRef/jabref/issues/8807)
 
 ### Fixed
 

src/main/java/org/jabref/gui/undo/CountingUndoManager.java

@@ -4,35 +4,81 @@
 import javax.swing.undo.UndoManager;
 import javax.swing.undo.UndoableEdit;
 
+import javafx.beans.property.BooleanProperty;
+import javafx.beans.property.IntegerProperty;
+import javafx.beans.property.ReadOnlyBooleanProperty;
+import javafx.beans.property.SimpleBooleanProperty;
+import javafx.beans.property.SimpleIntegerProperty;
+
 public class CountingUndoManager extends UndoManager {
 
     private int unchangedPoint;
-    private int current;
+
+    /**
+     * Indicates the number of edits aka balance of edits on the stack +1 when an edit is added/redone and -1 when an edit is undoed.
+     * */
+    private final IntegerProperty balanceProperty = new SimpleIntegerProperty(0);
+    private final BooleanProperty undoableProperty = new SimpleBooleanProperty(false);
+    private final BooleanProperty redoableProperty = new SimpleBooleanProperty(false);
 
     @Override
     public synchronized boolean addEdit(UndoableEdit edit) {
-        current++;
-        boolean result = super.addEdit(edit);
-        return result;
+        boolean editAdded = super.addEdit(edit);
+        if (editAdded) {
+            incrementBalance();
+            updateUndoableStatus();
+            updateRedoableStatus();
+            return true;
+        } else {
+            return false;
+        }
     }
 
     @Override
     public synchronized void undo() throws CannotUndoException {
         super.undo();
-        current--;
+        decrementBalance();
+        updateUndoableStatus();
+        updateRedoableStatus();
     }
 
     @Override
     public synchronized void redo() throws CannotUndoException {
         super.redo();
-        current++;
+        incrementBalance();
+        updateUndoableStatus();
+        updateRedoableStatus();
     }
 
     public synchronized void markUnchanged() {
-        unchangedPoint = current;
+        unchangedPoint = balanceProperty.get();
     }
 
     public synchronized boolean hasChanged() {
-        return current != unchangedPoint;
+        return balanceProperty.get() != unchangedPoint;
+    }
+
+    private void incrementBalance() {
+        balanceProperty.setValue(balanceProperty.getValue() + 1);
+    }
+
+    private void decrementBalance() {
+        balanceProperty.setValue(balanceProperty.getValue() - 1);
+    }
+
+    private void updateUndoableStatus() {
+        undoableProperty.setValue(canUndo());
+    }
+
+    private void updateRedoableStatus() {
+        redoableProperty.setValue(canRedo());
+    }
+
+    public ReadOnlyBooleanProperty getUndoableProperty() {
+        return undoableProperty;
+    }
+
+    public ReadOnlyBooleanProperty getRedoableProperty() {
+        return redoableProperty;
     }
 }

src/main/java/org/jabref/gui/undo/RedoAction.java

@@ -7,7 +7,6 @@
 import org.jabref.gui.DialogService;
 import org.jabref.gui.LibraryTab;
 import org.jabref.gui.StateManager;
-import org.jabref.gui.actions.ActionHelper;
 import org.jabref.gui.actions.SimpleCommand;
 import org.jabref.logic.l10n.Localization;
 
@@ -22,9 +21,10 @@ public RedoAction(Supplier<LibraryTab> tabSupplier, DialogService dialogService,
         this.tabSupplier = tabSupplier;
         this.dialogService = dialogService;
 
-        // TODO: Rework the UndoManager to something like the following, if it had a property.
-        //  this.executable.bind(frame.getCurrentBasePanel().getUndoManager().canUndo())
-        this.executable.bind(ActionHelper.needsDatabase(stateManager));
+        stateManager.activeTabProperty().addListener((observable, oldValue, activeLibraryTab) -> {
+            activeLibraryTab.ifPresent(libraryTab ->
+                    this.executable.bind(libraryTab.getUndoManager().getRedoableProperty()));
+        });
     }
 
     @Override

src/main/java/org/jabref/gui/undo/UndoAction.java

@@ -7,7 +7,6 @@
 import org.jabref.gui.DialogService;
 import org.jabref.gui.LibraryTab;
 import org.jabref.gui.StateManager;
-import org.jabref.gui.actions.ActionHelper;
 import org.jabref.gui.actions.SimpleCommand;
 import org.jabref.logic.l10n.Localization;
 
@@ -22,9 +21,10 @@ public UndoAction(Supplier<LibraryTab> tabSupplier, DialogService dialogService,
         this.tabSupplier = tabSupplier;
         this.dialogService = dialogService;
 
-        // TODO: Rework the UndoManager to something like the following, if it had a property.
-        //  this.executable.bind(frame.getCurrentBasePanel().getUndoManager().canUndo())
-        this.executable.bind(ActionHelper.needsDatabase(stateManager));
+        stateManager.activeTabProperty().addListener((observable, oldValue, activeLibraryTab) -> {
+            activeLibraryTab.ifPresent(libraryTab ->
+                    this.executable.bind(libraryTab.getUndoManager().getUndoableProperty()));
+        });
     }
 
     @Override