[GEF] Fully migrate to the GEF TreeViewer

This removes our copy of the `TreeViewerEditPart` and `TreeViewer` in
favor of the upstream classes. In order to use the GEF viewer directly,
a virtual `DesignComponent` edit part needs to be used as contents,
holding the `Tree` widget. Otherwise the edit part of the first model is
not shown.

Author: ptziegler

org.eclipse.wb.core.databinding/src/org/eclipse/wb/internal/core/databinding/ui/BindingElementsComposite.java

@@ -19,20 +19,16 @@
 import org.eclipse.wb.internal.core.databinding.Messages;
 import org.eclipse.wb.internal.core.databinding.model.IBindingInfo;
 import org.eclipse.wb.internal.core.databinding.model.IDatabindingsProvider;
+import org.eclipse.wb.internal.core.editor.TreeTransfer;
 import org.eclipse.wb.internal.core.utils.execution.ExecutionUtils;
 import org.eclipse.wb.internal.core.utils.ui.GridDataFactory;
 import org.eclipse.wb.internal.core.utils.ui.GridLayoutFactory;
 import org.eclipse.wb.internal.core.utils.ui.TableFactory;
-import org.eclipse.wb.internal.gef.tree.dnd.TreeTransfer;
 
 import org.eclipse.jface.dialogs.IDialogSettings;
 import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.jface.viewers.ArrayContentProvider;
-import org.eclipse.jface.viewers.DoubleClickEvent;
-import org.eclipse.jface.viewers.IDoubleClickListener;
-import org.eclipse.jface.viewers.ISelectionChangedListener;
 import org.eclipse.jface.viewers.IStructuredSelection;
-import org.eclipse.jface.viewers.SelectionChangedEvent;
 import org.eclipse.jface.viewers.StructuredSelection;
 import org.eclipse.jface.viewers.TableViewer;
 import org.eclipse.jface.viewers.ViewerDropAdapter;
@@ -47,9 +43,7 @@
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.events.SelectionListener;
 import org.eclipse.swt.widgets.Composite;
-import org.eclipse.swt.widgets.Event;
 import org.eclipse.swt.widgets.Label;
-import org.eclipse.swt.widgets.Listener;
 import org.eclipse.swt.widgets.Menu;
 import org.eclipse.swt.widgets.MenuItem;
 import org.eclipse.swt.widgets.Shell;
@@ -144,27 +138,18 @@ public BindingElementsComposite(Composite parent,
 		m_bindingViewer.setContentProvider(new ArrayContentProvider());
 		m_databindingsProvider.configureBindingViewer(settings, m_bindingViewer);
 		// viewer events
-		m_bindingViewer.addPostSelectionChangedListener(new ISelectionChangedListener() {
-			@Override
-			public void selectionChanged(SelectionChangedEvent event) {
-				IStructuredSelection selection = (IStructuredSelection) event.getSelection();
-				handleBindingSelection(selection);
-			}
+		m_bindingViewer.addPostSelectionChangedListener(event -> {
+			IStructuredSelection selection = (IStructuredSelection) event.getSelection();
+			handleBindingSelection(selection);
 		});
-		m_bindingViewer.addDoubleClickListener(new IDoubleClickListener() {
-			@Override
-			public void doubleClick(DoubleClickEvent event) {
-				if (m_editBindingListener != null && !UiUtils.isEmpty(m_bindingViewer.getSelection())) {
-					m_editBindingListener.widgetSelected(null);
-				}
+		m_bindingViewer.addDoubleClickListener(event -> {
+			if (m_editBindingListener != null && !UiUtils.isEmpty(m_bindingViewer.getSelection())) {
+				m_editBindingListener.widgetSelected(null);
 			}
 		});
-		m_bindingViewer.getControl().addListener(SWT.KeyDown, new Listener() {
-			@Override
-			public void handleEvent(Event event) {
-				if (event.character == SWT.DEL && !UiUtils.isEmpty(m_bindingViewer.getSelection())) {
-					deleteBindind();
-				}
+		m_bindingViewer.getControl().addListener(SWT.KeyDown, event -> {
+			if (event.character == SWT.DEL && !UiUtils.isEmpty(m_bindingViewer.getSelection())) {
+				deleteBindind();
 			}
 		});
 		setupDragAndDrop();

org.eclipse.wb.core.databinding/src/org/eclipse/wb/internal/core/databinding/ui/editor/contentproviders/ChooseClassAndPropertiesUiContentProvider.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2011, 2024 Google, Inc.
+ * Copyright (c) 2011, 2026 Google, Inc. 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
@@ -14,6 +14,7 @@
 
 import org.eclipse.wb.internal.core.databinding.Messages;
 import org.eclipse.wb.internal.core.databinding.ui.UiUtils;
+import org.eclipse.wb.internal.core.editor.TreeTransfer;
 import org.eclipse.wb.internal.core.utils.ui.GridDataFactory;
 import org.eclipse.wb.internal.core.utils.ui.GridLayoutFactory;
 

…ditor/contentproviders/TreeTransfer.java …b/internal/core/editor/TreeTransfer.javaorg.eclipse.wb.core.databinding/src/org/eclipse/wb/internal/core/databinding/ui/editor/contentproviders/TreeTransfer.java renamed to org.eclipse.wb.core.java/src/org/eclipse/wb/internal/core/editor/TreeTransfer.java org.eclipse.wb.core.databinding/src/org/eclipse/wb/internal/core/databinding/ui/editor/contentproviders/TreeTransfer.java renamed to org.eclipse.wb.core.java/src/org/eclipse/wb/internal/core/editor/TreeTransfer.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2011 Google, Inc.
+ * Copyright (c) 2011, 2026 Google, Inc. 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
@@ -10,7 +10,7 @@
  * Contributors:
  *    Google, Inc. - initial API and implementation
  *******************************************************************************/
-package org.eclipse.wb.internal.core.databinding.ui.editor.contentproviders;
+package org.eclipse.wb.internal.core.editor;
 
 import org.eclipse.swt.dnd.ByteArrayTransfer;
 import org.eclipse.swt.dnd.TransferData;
@@ -23,7 +23,7 @@
  * @author lobas_av
  * @coverage bindings.ui
  */
-final class TreeTransfer extends ByteArrayTransfer {
+public final class TreeTransfer extends ByteArrayTransfer {
 	public static final TreeTransfer INSTANCE = new TreeTransfer();
 	private static final String TYPE_NAME = "Tree content provider bindings tranfser";
 	private static final int TYPE_ID = registerType(TYPE_NAME);

org.eclipse.wb.core.java/src/org/eclipse/wb/internal/core/gef/tools/TabOrderTool.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2011, 2025 Google, Inc. and others.
+ * Copyright (c) 2011, 2026 Google, Inc. 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
@@ -195,8 +195,7 @@ protected boolean handleButtonDown(int button) {
 	@Override
 	protected void updateTargetUnderMouse() {
 		// find on clickable layer
-		EditPart editPart =
-				getCurrentViewer().findObjectAtExcluding(
+		EditPart editPart = ((IEditPartViewer) getCurrentViewer()).findObjectAtExcluding(
 						getLocation(),
 						getExclusionSet(),
 						getTargetingConditional(),

org.eclipse.wb.core.java/src/org/eclipse/wb/internal/core/gefTree/EditPartFactory2.java

@@ -19,9 +19,9 @@
 import org.eclipse.wb.internal.core.gefTree.part.FlowContainerGroupEditPart;
 import org.eclipse.wb.internal.core.model.nonvisual.AbstractArrayObjectInfo;
 import org.eclipse.wb.internal.core.model.nonvisual.FlowContainerGroupInfo;
-import org.eclipse.wb.internal.gef.tree.TreeViewer;
 
 import org.eclipse.gef.EditPart;
+import org.eclipse.gef.ui.parts.TreeViewer;
 
 /**
  * Generic implementation of {@link IEditPartFactory} for {@link TreeViewer} that redirects

org.eclipse.wb.core.java/src/org/eclipse/wb/internal/core/model/property/order/ReorderDialog.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2011, 2023 Google, Inc.
+ * Copyright (c) 2011, 2026 Google, Inc. 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
@@ -15,13 +15,13 @@
 import org.eclipse.wb.core.model.AbstractComponentInfo;
 import org.eclipse.wb.core.model.JavaInfo;
 import org.eclipse.wb.internal.core.DesignerPlugin;
+import org.eclipse.wb.internal.core.editor.TreeTransfer;
 import org.eclipse.wb.internal.core.model.ModelMessages;
 import org.eclipse.wb.internal.core.model.util.ObjectsLabelProvider;
 import org.eclipse.wb.internal.core.utils.ui.GridDataFactory;
 import org.eclipse.wb.internal.core.utils.ui.GridLayoutFactory;
 import org.eclipse.wb.internal.core.utils.ui.TableFactory;
 import org.eclipse.wb.internal.core.utils.ui.dialogs.ResizableDialog;
-import org.eclipse.wb.internal.gef.tree.dnd.TreeTransfer;
 
 import org.eclipse.jface.viewers.ArrayContentProvider;
 import org.eclipse.jface.viewers.CheckboxTableViewer;

org.eclipse.wb.core/META-INF/MANIFEST.MF

@@ -495,8 +495,6 @@ Export-Package: org.eclipse.wb.core.branding,
    org.eclipse.wb.swing,
    org.eclipse.wb.swt",
  org.eclipse.wb.internal.gef.graphical;x-friends:="org.eclipse.wb.tests,org.eclipse.wb.core.java",
- org.eclipse.wb.internal.gef.tree;x-friends:="org.eclipse.wb.tests,org.eclipse.wb.core.java",
- org.eclipse.wb.internal.gef.tree.dnd;x-friends:="org.eclipse.wb.core.databinding,org.eclipse.wb.core.java,org.eclipse.wb.tests",
  org.eclipse.wb.internal.gef.tree.policies;x-internal:=true,
  org.eclipse.wb.internal.gef.tree.tools;x-internal:=true
 Import-Package: org.apache.commons.collections4;version="[4.4.0,5.0.0)",

org.eclipse.wb.core/src-gef/org/eclipse/wb/gef/core/tools/Tool.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2011, 2025 Google, Inc. and others.
+ * Copyright (c) 2011, 2026 Google, Inc. 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
@@ -69,13 +69,6 @@ public final boolean isActive() {
 		return getFlag(FLAG_ACTIVE);
 	}
 
-	/**
-	 * Get {@link IEditPartViewer}.
-	 */
-	public final IEditPartViewer getCurrentViewer() {
-		return (IEditPartViewer) super.getCurrentViewer();
-	}
-
 	/**
 	 * Returns the {@link EditDomain}.
 	 */

org.eclipse.wb.core/src-gef/org/eclipse/wb/gef/tree/DesignTreeEditPart.java

@@ -19,6 +19,8 @@
 import org.eclipse.gef.EditPolicy;
 import org.eclipse.gef.Request;
 import org.eclipse.gef.commands.Command;
+import org.eclipse.gef.editparts.AbstractTreeEditPart;
+import org.eclipse.swt.widgets.TreeItem;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -28,8 +30,12 @@
  *
  * @see {@link RequestProcessor}
  */
-@SuppressWarnings("removal")
-public abstract class DesignTreeEditPart extends TreeEditPart {
+public abstract class DesignTreeEditPart extends AbstractTreeEditPart {
+
+	@Override
+	public TreeItem getWidget() {
+		return (TreeItem) super.getWidget();
+	}
 
 	////////////////////////////////////////////////////////////////////////////
 	//