Make DirectEditManager properly handle changed cell editor state

The DirectEditManager maintains an own dirty state to identify if a
command has to be executed on commit. In case it has an underlying cell
editor, this is when the cell editor submits its change. However, a
dirty state is already tracked by the underlying cell editor in that
case and the two are not necessarily consistent.
The DirectEditManager only updates its dirty state on a
`editorValueChanged` event from the cell editor, which is by definition
only sent on textual input changes. In case a selection is made, such as
in case of the ComboBoxCellEditor, no such `editorValueChanged` event is
submitted but only the `applyEditorValue` event is triggered. In
consequences, changes in ComboBoxCellEditors are currently not properly
converted into according commands by the DirectEditManager.

This change adapts the DirectEditManager to consider the dirty state of
the underlying cell editor in addition to a potentially set custom dirty
state on the DirectEditManager itself.

Author: HeikoKlare

org.eclipse.gef.tests/src/org/eclipse/gef/test/DirectEditManagerTest.java

@@ -0,0 +1,133 @@
+/*******************************************************************************
+ * Copyright (c) 2025 Vector Informatik GmbH and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *******************************************************************************/
+package org.eclipse.gef.test;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Collection;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import org.eclipse.swt.widgets.Composite;
+import org.eclipse.swt.widgets.Control;
+import org.eclipse.swt.widgets.Shell;
+
+import org.eclipse.jface.viewers.CellEditor;
+import org.eclipse.jface.viewers.ComboBoxCellEditor;
+import org.eclipse.ui.PlatformUI;
+
+import org.eclipse.draw2d.Figure;
+import org.eclipse.draw2d.IFigure;
+import org.eclipse.draw2d.geometry.Point;
+
+import org.eclipse.gef.EditDomain;
+import org.eclipse.gef.EditPart;
+import org.eclipse.gef.GraphicalEditPart;
+import org.eclipse.gef.Request;
+import org.eclipse.gef.commands.Command;
+import org.eclipse.gef.editparts.AbstractGraphicalEditPart;
+import org.eclipse.gef.tools.DirectEditManager;
+import org.eclipse.gef.ui.parts.AbstractEditPartViewer;
+
+import org.junit.jupiter.api.Test;
+
+public class DirectEditManagerTest {
+
+	@SuppressWarnings("static-method")
+	@Test
+	public void testComboCellEditorChangeProcessed() {
+		Shell shell = PlatformUI.getWorkbench().getDisplay()
+				.syncCall(() -> PlatformUI.getWorkbench().getDisplay().getActiveShell());
+		EditDomain editDomain = new EditDomain();
+		TestDirectEditManager editManager = new TestDirectEditManager(createDummyEditPart(shell, editDomain));
+		AtomicBoolean comboChangeCommandSubmitted = new AtomicBoolean();
+		editDomain.getCommandStack().addCommandStackEventListener(event -> comboChangeCommandSubmitted.set(true));
+
+		PlatformUI.getWorkbench().getDisplay().syncExec(() -> {
+			editManager.show();
+			// Change value of combo cell editor
+			editManager.getCellEditor().setValue(0);
+			// Make combo cell editor lose focus to apply its value
+			shell.setFocus();
+		});
+
+		assertTrue(comboChangeCommandSubmitted.get());
+	}
+
+	private static class TestDirectEditManager extends DirectEditManager {
+		public TestDirectEditManager(GraphicalEditPart source) {
+			super(source, ComboBoxCellEditor.class, cellEditor -> {
+			});
+		}
+
+		@Override
+		protected CellEditor createCellEditorOn(Composite composite) {
+			return new ComboBoxCellEditor(composite, new String[] { "test" }); //$NON-NLS-1$
+		}
+
+		@Override
+		public CellEditor getCellEditor() {
+			return super.getCellEditor();
+		}
+
+		@Override
+		public void showFeedback() {
+		}
+
+		@Override
+		protected void initCellEditor() {
+		}
+	}
+
+	private static GraphicalEditPart createDummyEditPart(Control control, EditDomain editDomain) {
+		return new AbstractGraphicalEditPart() {
+			@Override
+			protected void createEditPolicies() {
+			}
+
+			@Override
+			public org.eclipse.gef.EditPartViewer getViewer() {
+				return new AbstractEditPartViewer() {
+					@Override
+					public EditPart findObjectAtExcluding(Point location, Collection<IFigure> exclusionSet,
+							Conditional conditional) {
+						return null;
+					}
+
+					@Override
+					public Control createControl(Composite parent) {
+						return parent;
+					}
+
+					@Override
+					public Control getControl() {
+						return control;
+					}
+
+					@Override
+					public org.eclipse.gef.EditDomain getEditDomain() {
+						return editDomain;
+					}
+				};
+			}
+
+			@Override
+			public Command getCommand(Request request) {
+				return new Command() {
+				};
+			}
+
+			@Override
+			protected IFigure createFigure() {
+				return new Figure();
+			}
+		};
+	}
+
+}

org.eclipse.gef.tests/src/org/eclipse/gef/test/GEFTestSuite.java

@@ -31,7 +31,8 @@
 	RulerLayoutTests.class,
 	GraphicalViewerTest.class,
 	PaletteColorProviderTest.class,
-	SWTBotTestSuite.class
+	SWTBotTestSuite.class,
+	DirectEditManagerTest.class
 })
 public class GEFTestSuite {
 }

org.eclipse.gef/src/org/eclipse/gef/tools/DirectEditManager.java

@@ -62,7 +62,7 @@ public abstract class DirectEditManager {
 	private IFigure cellEditorFrame;
 	private ICellEditorListener cellEditorListener;
 	private boolean showingFeedback;
-	private boolean dirty;
+	private boolean customDirtyState;
 	private DirectEditRequest request;
 	private CellEditorLocator locator;
 	private GraphicalEditPart source;
@@ -121,7 +121,7 @@ protected void bringDown() {
 			setCellEditor(null);
 		}
 		request = null;
-		dirty = false;
+		customDirtyState = false;
 	}
 
 	/**
@@ -260,7 +260,10 @@ protected CellEditorLocator getLocator() {
 	}
 
 	protected void handleValueChanged() {
-		setDirty(true);
+		CellEditor cellEditor = getCellEditor();
+		if (cellEditor == null) {
+			setDirty(true);
+		}
 		showFeedback();
 		placeCellEditor();
 	}
@@ -332,7 +335,11 @@ public void partDeactivated(EditPart editpart) {
 	 * @return <code>true</code> if the cell editor is dirty
 	 */
 	protected boolean isDirty() {
-		return dirty;
+		CellEditor cellEditor = getCellEditor();
+		if (cellEditor == null) {
+			return customDirtyState;
+		}
+		return cellEditor.isDirty();
 	}
 
 	private void placeCellEditorFrame() {
@@ -368,7 +375,7 @@ protected void setCellEditor(CellEditor editor) {
 	 * @param value the dirty property
 	 */
 	protected void setDirty(boolean value) {
-		dirty = value;
+		customDirtyState = value;
 	}
 
 	/**