[GEF] Remove forked RootEditPart class for tree viewer

org.eclipse.wb.core/src-gef/org/eclipse/wb/internal/gef/tree/TreeViewer.java

@@ -17,7 +17,9 @@
 import org.eclipse.draw2d.geometry.Point;
 import org.eclipse.gef.EditDomain;
 import org.eclipse.gef.EditPart;
+import org.eclipse.gef.RootEditPart;
 import org.eclipse.gef.TreeEditPart;
+import org.eclipse.gef.editparts.RootTreeEditPart;
 import org.eclipse.jface.viewers.StructuredSelection;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.SelectionEvent;
@@ -39,7 +41,7 @@
  */
 public class TreeViewer extends AbstractEditPartViewer {
 	private Tree m_tree;
-	private RootEditPart m_rootEditPart;
+	private RootTreeEditPart m_rootEditPart;
 	private TreeEventManager m_eventManager;
 
 	@Override
@@ -48,7 +50,8 @@ public Control createControl(Composite parent) {
 		// handle SWT events
 		m_eventManager = new TreeEventManager(m_tree, this);
 		// create root EditPart
-		m_rootEditPart = new RootEditPart();
+		m_rootEditPart = new RootTreeEditPart();
+		m_rootEditPart.setWidget(m_tree);
 		m_rootEditPart.setViewer(this);
 		m_rootEditPart.activate();
 		setRootEditPart(m_rootEditPart);

org.eclipse.wb.core/src/org/eclipse/wb/internal/core/editor/structure/components/ComponentsTreePage.java

@@ -20,6 +20,7 @@
 import org.eclipse.wb.internal.core.editor.Messages;
 import org.eclipse.wb.internal.core.editor.structure.IPage;
 import org.eclipse.wb.internal.core.gefTree.EditPartFactory;
+import org.eclipse.wb.internal.core.model.ObjectInfoContainer;
 import org.eclipse.wb.internal.core.model.ObjectReferenceInfo;
 import org.eclipse.wb.internal.core.preferences.IPreferenceConstants;
 import org.eclipse.wb.internal.core.utils.execution.ExecutionUtils;
@@ -265,7 +266,7 @@ public void setInput(EditPartViewer editPartViewer, ObjectInfo rootObject) {
 		// refresh objects viewer
 		m_viewer.removeSelectionChangedListener(m_selectionListener_Tree);
 		try {
-			m_viewer.setInput(m_rootObject);
+			m_viewer.setInput(m_rootObject == null ? null : new ObjectInfoContainer(m_rootObject));
 		} finally {
 			m_viewer.addSelectionChangedListener(m_selectionListener_Tree);
 		}

org.eclipse.wb.core/src/org/eclipse/wb/internal/core/gefTree/EditPartFactory.java

@@ -16,8 +16,10 @@
 import org.eclipse.wb.core.gefTree.part.ObjectEditPart;
 import org.eclipse.wb.core.model.ObjectInfo;
 import org.eclipse.wb.gef.core.IEditPartFactory;
+import org.eclipse.wb.internal.core.gefTree.part.ObjectContainerEditPart;
 import org.eclipse.wb.internal.core.gefTree.part.menu.MenuEditPart;
 import org.eclipse.wb.internal.core.gefTree.part.menu.MenuItemEditPart;
+import org.eclipse.wb.internal.core.model.ObjectInfoContainer;
 import org.eclipse.wb.internal.core.model.menu.IMenuInfo;
 import org.eclipse.wb.internal.core.model.menu.IMenuItemInfo;
 import org.eclipse.wb.internal.core.model.menu.MenuObjectInfoUtils;
@@ -104,6 +106,9 @@ private EditPart createEditPartPure(EditPart context, Object model) {
 		if (model instanceof ObjectInfo) {
 			return new ObjectEditPart((ObjectInfo) model);
 		}
+		if (model instanceof ObjectInfoContainer) {
+			return new ObjectContainerEditPart((ObjectInfoContainer) model);
+		}
 		// no EditPart found
 		return null;
 	}

org.eclipse.wb.core/src/org/eclipse/wb/internal/core/gefTree/part/ObjectContainerEditPart.java

@@ -0,0 +1,41 @@
+/*******************************************************************************
+ * Copyright (c) 2026 Patrick Ziegler 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
+ * https://www.eclipse.org/legal/epl-2.0.
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *    Patrick Ziegler - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.wb.internal.core.gefTree.part;
+
+import org.eclipse.wb.internal.core.model.ObjectInfoContainer;
+import org.eclipse.wb.internal.gef.tree.TreeViewer;
+
+import org.eclipse.gef.editparts.AbstractTreeEditPart;
+
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * Edit part for the {@link ObjectInfoContainer} which is used as input for the
+ * {@link TreeViewer}. This edit part is not shown.
+ */
+public class ObjectContainerEditPart extends AbstractTreeEditPart {
+	public ObjectContainerEditPart(ObjectInfoContainer model) {
+		setModel(model);
+	}
+
+	@Override
+	protected List<?> getModelChildren() {
+		return Collections.singletonList(getModel().objectInfo());
+	}
+
+	@Override
+	public ObjectInfoContainer getModel() {
+		return (ObjectInfoContainer) super.getModel();
+	}
+}

org.eclipse.wb.core/src/org/eclipse/wb/internal/core/model/ObjectInfoContainer.java

@@ -0,0 +1,24 @@
+/*******************************************************************************
+ * Copyright (c) 2026 Patrick Ziegler 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
+ * https://www.eclipse.org/legal/epl-2.0.
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *    Patrick Ziegler - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.wb.internal.core.model;
+
+import org.eclipse.wb.core.model.ObjectInfo;
+import org.eclipse.wb.internal.gef.tree.TreeViewer;
+
+/**
+ * Container for an {@link ObjectInfo} to be used as input for the
+ * {@link TreeViewer}. This container is not shown.
+ */
+public record ObjectInfoContainer(ObjectInfo objectInfo) {
+	// Accessors created automatically by Java
+}

org.eclipse.wb.tests/src/org/eclipse/wb/tests/gef/TreeCreateToolTest.java

@@ -66,7 +66,7 @@ public void test_Move_1() throws Exception {
 		//
 		ILayoutEditPolicy ipolicy = (request, editPart) -> true;
 		//
-		TreeEditPart parent = addEditPart(m_viewer.getRootEditPart(), "parent", actualLogger, ipolicy);
+		TreeEditPart parent = addEditPart(m_contents, "parent", actualLogger, ipolicy);
 		TreeEditPart child1 = addEditPart(parent, "child1", actualLogger, ipolicy);
 		TreeEditPart parent1 = addEditPart(parent, "parent1", actualLogger, ipolicy);
 		TreeEditPart parent2 = addEditPart(parent, "parent2", actualLogger, ipolicy);
@@ -157,7 +157,7 @@ public void test_Move_2() throws Exception {
 		//
 		ILayoutEditPolicy ipolicy = (request, editPart) -> true;
 		//
-		TreeEditPart parent = addEditPart(m_viewer.getRootEditPart(), "parent", actualLogger, ipolicy);
+		TreeEditPart parent = addEditPart(m_contents, "parent", actualLogger, ipolicy);
 		TreeEditPart child1 = addEditPart(parent, "child1", actualLogger, null);
 		addEditPart(parent, "parent1", actualLogger, ipolicy);
 		//
@@ -200,7 +200,7 @@ public void test_Move_3() throws Exception {
 		//
 		ILayoutEditPolicy ipolicy = (request, editPart) -> true;
 		//
-		TreeEditPart parent = addEditPart(m_viewer.getRootEditPart(), "parent", actualLogger, (request, editPart) -> !"child1".equals(editPart.getModel()));
+		TreeEditPart parent = addEditPart(m_contents, "parent", actualLogger, (request, editPart) -> !"child1".equals(editPart.getModel()));
 		TreeEditPart child1 = addEditPart(parent, "child1", actualLogger, ipolicy);
 		addEditPart(parent, "parent1", actualLogger, ipolicy);
 		//

org.eclipse.wb.tests/src/org/eclipse/wb/tests/gef/TreeDragToolTest.java

@@ -53,7 +53,7 @@ public void test_DoubleClick() throws Exception {
 		RequestsLogger actualLogger = new RequestsLogger();
 		//
 		ILayoutEditPolicy ipolicy = (request, editPart) -> true;
-		TreeEditPart parent = addEditPart(m_viewer.getRootEditPart(), "parent", actualLogger, ipolicy);
+		TreeEditPart parent = addEditPart(m_contents, "parent", actualLogger, ipolicy);
 		TreeEditPart child1 = addEditPart(parent, "child1", actualLogger, ipolicy);
 		//
 		refreshTreeParst(parent);
@@ -94,7 +94,7 @@ public void test_Drag_1() throws Exception {
 		//
 		ILayoutEditPolicy ipolicy = (request, editPart) -> true;
 		//
-		TreeEditPart parent = addEditPart(m_viewer.getRootEditPart(), "parent", actualLogger, ipolicy);
+		TreeEditPart parent = addEditPart(m_contents, "parent", actualLogger, ipolicy);
 		TreeEditPart child1 = addEditPart(parent, "child1", actualLogger, ipolicy);
 		TreeEditPart child2 = addEditPart(parent, "child2", actualLogger, ipolicy);
 		TreeEditPart child3 = addEditPart(parent, "child3", actualLogger, ipolicy);
@@ -196,7 +196,7 @@ public void test_Drag_2() throws Exception {
 		//
 		ILayoutEditPolicy ipolicy = (request, editPart) -> true;
 		//
-		TreeEditPart parent = addEditPart(m_viewer.getRootEditPart(), "parent", actualLogger, ipolicy);
+		TreeEditPart parent = addEditPart(m_contents, "parent", actualLogger, ipolicy);
 		TreeEditPart child1 = addEditPart(parent, "child1", actualLogger, null);
 		addEditPart(parent, "child2", actualLogger, ipolicy);
 		TreeEditPart child3 = addEditPart(parent, "child3", actualLogger, ipolicy);
@@ -244,7 +244,7 @@ public void test_Drag_3() throws Exception {
 		//
 		ILayoutEditPolicy ipolicy = (request, editPart) -> true;
 		//
-		TreeEditPart parent = addEditPart(m_viewer.getRootEditPart(), "parent", actualLogger, (request, editPart) -> !"child1".equals(editPart.getModel()));
+		TreeEditPart parent = addEditPart(m_contents, "parent", actualLogger, (request, editPart) -> !"child1".equals(editPart.getModel()));
 		TreeEditPart child1 = addEditPart(parent, "child1", actualLogger, ipolicy);
 		addEditPart(parent, "child2", actualLogger, ipolicy);
 		TreeEditPart child3 = addEditPart(parent, "child3", actualLogger, ipolicy);

org.eclipse.wb.tests/src/org/eclipse/wb/tests/gef/TreeToolTest.java

@@ -28,6 +28,7 @@
 import org.eclipse.gef.Tool;
 import org.eclipse.gef.TreeEditPart;
 import org.eclipse.gef.commands.Command;
+import org.eclipse.gef.editparts.AbstractTreeEditPart;
 import org.eclipse.gef.requests.SelectionRequest;
 import org.eclipse.swt.widgets.Display;
 import org.eclipse.swt.widgets.Shell;
@@ -47,6 +48,7 @@ public abstract class TreeToolTest extends GefTestCase {
 	protected EditDomain m_domain;
 	protected TreeViewer m_viewer;
 	protected EventSender m_sender;
+	protected TreeEditPart m_contents;
 
 	////////////////////////////////////////////////////////////////////////////
 	//
@@ -66,11 +68,14 @@ public Tool getDefaultTool() {
 				return null;
 			}
 		};
+		// create contents
+		m_contents = new RequestContentsTreeEditPart();
 		// create viewer
 		m_viewer = new TreeViewer();
 		m_viewer.createControl(m_shell);
 		m_viewer.getControl().setSize(500, 400);
 		m_viewer.setEditDomain(m_domain);
+		m_viewer.setContents(m_contents);
 		// create sender
 		m_sender = new EventSender(m_viewer.getControl());
 	}
@@ -144,11 +149,7 @@ protected final TreeEditPart addEditPart(EditPart parentEditPart,
 			RequestsLogger actualLogger,
 			ILayoutEditPolicy ipolicy) throws Exception {
 		RequestTreeEditPart editPart = new RequestTreeEditPart(name, actualLogger, ipolicy);
-		if (m_viewer.getRootEditPart() == parentEditPart) {
-			m_viewer.getRootEditPart().setContents(editPart);
-		} else {
-			addChildEditPart(parentEditPart, editPart);
-		}
+		addChildEditPart(parentEditPart, editPart);
 		return editPart;
 	}
 
@@ -168,6 +169,10 @@ protected static final void expandAll(TreeViewer viewer) {
 	// EditPart implementation
 	//
 	////////////////////////////////////////////////////////////////////////////
+	private static final class RequestContentsTreeEditPart extends AbstractTreeEditPart {
+		// Stub
+	}
+
 	private static final class RequestTreeEditPart extends DesignTreeEditPart {
 		private final String m_name;
 		private final RequestsLogger m_logger;