Allow to hide the context menu in the perspective switcher

Eclipse RCP applications running in the compatibility mode have
currently no way of hiding the menu in the perspective switcher. This
introduces a model tag in PerspectiveSwitcher which can be set at
startup or runtime and will prevent the display of a menu in the
perspective switcher.

Author: vogella

bundles/org.eclipse.ui.workbench/eclipseui/org/eclipse/e4/ui/workbench/addons/perspectiveswitcher/PerspectiveSwitcher.java

@@ -102,6 +102,7 @@ public class PerspectiveSwitcher {
 	 * The ID of the perspective switcher
 	 */
 	public static final String PERSPECTIVE_SWITCHER_ID = "org.eclipse.e4.ui.PerspectiveSwitcher"; //$NON-NLS-1$
+	public static final String NO_MENU = "NoMenu"; //$NON-NLS-1$
 
 	/**
 	 * The event {@link IEventBroker}.
@@ -277,6 +278,9 @@ void createWidget(Composite parent, MToolControl toolControl) {
 		comp.addDisposeListener(e -> dispose());
 
 		perspSwitcherToolbar.addMenuDetectListener(e -> {
+			if (perspSwitcherToolControl.getTags().contains(NO_MENU)) {
+				return;
+			}
 			ToolBar tb = (ToolBar) e.widget;
 			Point p = new Point(e.x, e.y);
 			p = perspSwitcherToolbar.getDisplay().map(null, perspSwitcherToolbar, p);