Initial PoC for pure GEF-based palette viewer

This implements the WindowBuilder palette using the native GEF
implementation. While it implementation is functional, it is still
missing functionality like theming and drag & drop, which is why the new
palette has to be expiliclty enabled using the "wbp.gef.palette" system
property.

org.eclipse.wb.core.java/src/org/eclipse/wb/internal/core/editor/palette/DesignerEditDomain.java

@@ -0,0 +1,51 @@
+/*******************************************************************************
+ * Copyright (c) 2025 Patrick Ziegler and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *    Patrick Ziegler - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.wb.internal.core.editor.palette;
+
+import org.eclipse.gef.EditDomain;
+import org.eclipse.gef.EditPartViewer;
+import org.eclipse.gef.Tool;
+import org.eclipse.gef.ui.palette.PaletteViewer;
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.events.MouseEvent;
+
+/**
+ * Custom edit domain used for the {@link PaletteViewer} that keeps track of
+ * whether the CTRL key is pressed while creating a tool. If so, the tool
+ * remains active after being used, allowing the user to add multiple elements
+ * without having to re-select the entry every time.
+ */
+public class DesignerEditDomain extends EditDomain {
+
+	private boolean reload;
+
+	@Override
+	public void mouseUp(MouseEvent mouseEvent, EditPartViewer viewer) {
+		Tool tool = getActiveTool();
+		if (tool != null) {
+			try {
+				reload = (mouseEvent.stateMask & SWT.CTRL) != 0;
+				tool.mouseUp(mouseEvent, viewer);
+			} finally {
+				reload = false;
+			}
+		}
+	}
+
+	/**
+	 * Returns {@code true}, when called from within the
+	 * {@link #mouseUp(MouseEvent, EditPartViewer)} method while the CTRL key is
+	 * pressed.
+	 */
+	public boolean isReload() {
+		return reload;
+	}
+}

org.eclipse.wb.core.java/src/org/eclipse/wb/internal/core/editor/palette/DesignerPalette.java

@@ -28,7 +28,9 @@
 import org.eclipse.wb.core.model.JavaInfo;
 import org.eclipse.wb.core.model.broadcast.ObjectEventListener;
 import org.eclipse.wb.gef.core.IEditPartViewer;
+import org.eclipse.wb.gef.core.tools.Tool;
 import org.eclipse.wb.gef.graphical.tools.SelectionTool;
+import org.eclipse.wb.internal.core.EnvironmentUtils;
 import org.eclipse.wb.internal.core.editor.DesignPage;
 import org.eclipse.wb.internal.core.editor.palette.command.CategoryMoveCommand;
 import org.eclipse.wb.internal.core.editor.palette.command.CategoryRemoveCommand;
@@ -59,6 +61,9 @@
 import org.eclipse.core.runtime.jobs.IJobManager;
 import org.eclipse.core.runtime.jobs.Job;
 import org.eclipse.core.runtime.preferences.InstanceScope;
+import org.eclipse.draw2d.FigureCanvas;
+import org.eclipse.gef.ui.palette.PaletteContextMenuProvider;
+import org.eclipse.gef.ui.palette.PaletteViewer;
 import org.eclipse.jface.action.IMenuManager;
 import org.eclipse.jface.window.Window;
 import org.eclipse.swt.SWT;
@@ -89,8 +94,11 @@ public class DesignerPalette {
 	private final String ENTRYINFO_CATEGORY = "org.eclipse.wb.swing.layouts";
 	private final boolean m_isMainPalette;
 	private final PluginPalettePreferences m_preferences;
-	private final PaletteComposite m_paletteComposite;
+	private final PaletteComposite m_legacyPaletteComposite;
 	private final DesignerPaletteOperations m_operations;
+	private final PaletteViewer m_paletteViewer;
+	private final FigureCanvas m_paletteComposite;
+	private final DesignerEditDomain m_paletteDomain;
 	private IEditPartViewer m_editPartViewer;
 	private JavaInfo m_rootJavaInfo;
 	private PaletteManager m_manager;
@@ -105,7 +113,22 @@ public DesignerPalette(Composite parent, int style, boolean isMainPalette) {
 		m_isMainPalette = isMainPalette;
 		m_operations = new DesignerPaletteOperations();
 		m_preferences = new PluginPalettePreferences();
-		m_paletteComposite = new PaletteComposite(parent, SWT.NONE);
+		if (EnvironmentUtils.isGefPalette()) {
+			m_legacyPaletteComposite = null;
+			m_paletteDomain = new DesignerEditDomain();
+			m_paletteViewer = new PaletteViewer();
+			m_paletteViewer.enableVerticalScrollbar(true);
+			m_paletteViewer.setEditDomain(m_paletteDomain);
+			m_paletteViewer.setPaletteViewerPreferences(m_preferences);
+			m_paletteViewer.setContextMenu(new PaletteContextMenuProvider(m_paletteViewer));
+			m_paletteComposite = (FigureCanvas) m_paletteViewer.createControl(parent);
+			m_paletteComposite.setScrollbarsMode(SWT.NONE);
+		} else {
+			m_legacyPaletteComposite = new PaletteComposite(parent, SWT.NONE);
+			m_paletteDomain = null;
+			m_paletteViewer = null;
+			m_paletteComposite = null;
+		}
 	}
 
 	////////////////////////////////////////////////////////////////////////////
@@ -114,7 +137,7 @@ public DesignerPalette(Composite parent, int style, boolean isMainPalette) {
 	//
 	////////////////////////////////////////////////////////////////////////////
 	public Control getControl() {
-		return m_paletteComposite;
+		return m_legacyPaletteComposite != null ? m_legacyPaletteComposite : m_paletteComposite;
 	}
 
 	/**
@@ -125,6 +148,9 @@ public void setInput(IEditPartViewer editPartViewer,
 			String toolkitId) {
 		m_editPartViewer = editPartViewer;
 		m_rootJavaInfo = rootJavaInfo;
+		if (m_legacyPaletteComposite == null) {
+			editPartViewer.getEditDomain().setPaletteViewer(m_paletteViewer);
+		}
 		//
 		if (m_rootJavaInfo != null) {
 			// cancel cache pre-loading jobs possibly scheduled and/or running
@@ -143,15 +169,21 @@ public void setInput(IEditPartViewer editPartViewer,
 			// configure preferences
 			{
 				m_preferences.setPrefix(toolkitId);
-				m_paletteComposite.setPreferences(m_preferences);
+				if (m_legacyPaletteComposite != null) {
+					m_legacyPaletteComposite.setPreferences(m_preferences);
+				}
 			}
 			// set site
 			IPaletteSite.Helper.setSite(m_rootJavaInfo, m_paletteSite);
 			// refresh palette on JavaInfo hierarchy refresh
 			rootJavaInfo.addBroadcastListener(new ObjectEventListener() {
 				@Override
 				public void refreshed() throws Exception {
-					if (m_paletteComposite.isDisposed()) {
+					if (m_legacyPaletteComposite != null && m_legacyPaletteComposite.isDisposed()) {
+						rootJavaInfo.removeBroadcastListener(this);
+						return;
+					}
+					if (m_paletteComposite != null && m_paletteComposite.isDisposed()) {
 						rootJavaInfo.removeBroadcastListener(this);
 						return;
 					}
@@ -279,6 +311,14 @@ public boolean isEnabled() {
 					public boolean activate(boolean reload) {
 						return entryInfo.createTool(reload) != null;
 					}
+
+					@Override
+					public Tool createTool() {
+						if (m_paletteDomain == null) {
+							return entryInfo.createTool(false);
+						}
+						return entryInfo.createTool(m_paletteDomain.isReload());
+					}
 				};
 				m_goodEntryInfos.add(entryInfo);
 				m_entryInfoToVisual.put(entryInfo, entry);
@@ -419,7 +459,11 @@ public void moveEntry(IEntry _entry, ICategory _targetCategory, IEntry _nextEntr
 				}
 			}
 		}
-		m_paletteComposite.setPalette(palette);
+		if (m_legacyPaletteComposite != null) {
+			m_legacyPaletteComposite.setPalette(palette);
+		} else {
+			m_paletteViewer.setPaletteRoot(palette);
+		}
 		configure_EditDomain_DefaultTool();
 	}
 
@@ -447,7 +491,11 @@ private void configure_EditDomain_DefaultTool() {
 				@Override
 				public void loadDefaultTool() {
 					if (m_defaultEntry != null) {
-						m_paletteComposite.selectEntry(m_defaultEntry, false);
+						if (m_legacyPaletteComposite != null) {
+							m_legacyPaletteComposite.selectEntry(m_defaultEntry, false);
+						} else {
+							m_paletteViewer.setActiveTool(m_defaultEntry);
+						}
 					} else {
 						editDomain.setActiveTool(new SelectionTool());
 					}
@@ -461,7 +509,9 @@ public void loadDefaultTool() {
 	 * Refreshes visual palette.
 	 */
 	private void refreshVisualPalette() {
-		m_paletteComposite.refreshPalette();
+		if (m_legacyPaletteComposite != null) {
+			m_legacyPaletteComposite.refreshPalette();
+		}
 	}
 
 	////////////////////////////////////////////////////////////////////////////
@@ -508,15 +558,19 @@ public void editPreferences() {
 			PalettePreferencesDialog dialog = new PalettePreferencesDialog(getShell(), m_preferences);
 			if (dialog.open() == Window.OK) {
 				dialog.commit();
-				m_paletteComposite.setPreferences(m_preferences);
+				if (m_legacyPaletteComposite != null) {
+					m_legacyPaletteComposite.setPreferences(m_preferences);
+				}
 			}
 		}
 
 		public void setIconsType(int iconsType) {
-			m_paletteComposite.setLayoutType(iconsType);
 			m_preferences.setLayoutSetting(iconsType);
-			m_paletteComposite.setPreferences(m_preferences);
-			m_paletteComposite.refreshComposite();
+			if (m_legacyPaletteComposite != null) {
+				m_legacyPaletteComposite.setLayoutType(iconsType);
+				m_legacyPaletteComposite.setPreferences(m_preferences);
+				m_legacyPaletteComposite.refreshComposite();
+			}
 		}
 
 		public EntryInfo getEntry(Object target) {

org.eclipse.wb.core/src/org/eclipse/wb/core/controls/palette/DesignerEntry.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2024 Patrick Ziegler and others.
+ * Copyright (c) 2024, 2025 Patrick Ziegler and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -19,7 +19,7 @@
 @SuppressWarnings("removal")
 public abstract class DesignerEntry extends ToolEntry implements IEntry {
 	public DesignerEntry(String label, String shortDescription, ImageDescriptor iconSmall) {
-		super(label, shortDescription, iconSmall, null);
+		super(label, shortDescription, iconSmall, iconSmall);
 	}
 
 	/**
@@ -36,9 +36,15 @@ public DesignerEntry(String label, String shortDescription, ImageDescriptor icon
 	 *
 	 * @return <code>true</code> if {@link DesignerEntry} was successfully
 	 *         activated.
+	 * @deprecated Call {@link #createTool()} instead and check for null-ness. The
+	 *             reload flag needs to be set in the edit domain. This method will
+	 *             be removed after the 2027-03 release.
 	 */
 	@Override
-	public abstract boolean activate(boolean reload);
+	@Deprecated(since = "1.19.0", forRemoval = true)
+	public boolean activate(boolean reload) {
+		return false;
+	}
 
 	/**
 	 * @noreference This method is not intended to be referenced by clients.

org.eclipse.wb.core/src/org/eclipse/wb/internal/core/EnvironmentUtils.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2011, 2024 Google, Inc. and others.
+ * Copyright (c) 2011, 2025 Google, Inc. and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -210,4 +210,15 @@ public static boolean isTestingTime() {
 	public static void setTestingTime(boolean value) {
 		System.setProperty(WBP_TESTING_TIME, value ? "true" : "false");
 	}
+
+	////////////////////////////////////////////////////////////////////////////
+	//
+	// Development
+	//
+	////////////////////////////////////////////////////////////////////////////
+	private static final String WBP_GEF_PALETTE = "wbp.gef.palette";
+
+	public static boolean isGefPalette() {
+		return Boolean.getBoolean(WBP_GEF_PALETTE);
+	}
 }

org.eclipse.wb.doc.user/html-src/whatsnew/index.asciidoc

@@ -1,9 +1,7 @@
-= What's New - v1.18.0
+= What's New - v1.19.0
 
-* Fixed IndexOutOfBoundsException when removing widgets while using JDK8
-* Dropped support for JSR296 (Swing Application Framework)
-* Removal of old amd64 binaries for Linux
+* Experimental GEF palette which can be enabled using the _wbp.gef.palette_ system property.
 
-For a full list of all changes, check the link:https://github.com/eclipse-windowbuilder/windowbuilder/milestone/10[1.18.0] milestone.
+For a full list of all changes, check the link:https://github.com/eclipse-windowbuilder/windowbuilder/milestone/11[1.19.0] milestone.
 
-What's new - link:v117.html[*v1.17.0*]
+What's new - link:v118.html[*v1.18.0*]

org.eclipse.wb.doc.user/html-src/whatsnew/v118.asciidoc

@@ -0,0 +1,9 @@
+= What's New - v1.18.0
+
+* Fixed IndexOutOfBoundsException when removing widgets while using JDK8
+* Dropped support for JSR296 (Swing Application Framework)
+* Removal of old amd64 binaries for Linux
+
+For a full list of all changes, check the link:https://github.com/eclipse-windowbuilder/windowbuilder/milestone/10[1.18.0] milestone.
+
+What's new - link:v117.html[*v1.17.0*]