Bug 317417 [Model] StackElement should be abstract and interface
StackElement is only a marker for improved containment hierarchies. We should at least make it abstract but also as an interface like WindowElement, ...
bundles/org.eclipse.e4.ui.model.workbench.edit/src/org/eclipse/e4/ui/model/application/ui/menu/provider/MenuItemProvider.java
* @generated NOT
	 */
	@Override
	public String getText(Object object) {
		String label = ((MMenu)object).getLabel();
		return label == null || label.length() == 0 ?
			getString("_UI_Menu_type") : 
			getString("_UI_Menu_type") + " - " + label; 
	}
	/**
	 * This handles model notifications by calling {@link #updateChildren} to update any cached
	 * children and by creating a viewer notification, which it passes to {@link #fireNotifyChanged}.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 * @generated
	 */
	@Override
	public void notifyChanged(Notification notification) {
		updateChildren(notification);
		switch (notification.getFeatureID(MMenu.class)) {
			case MenuPackageImpl.MENU__ENABLED:
				fireNotifyChanged(new ViewerNotification(notification, notification.getNotifier(), false, true));
				return;
			case MenuPackageImpl.MENU__CHILDREN:
				fireNotifyChanged(new ViewerNotification(notification, notification.getNotifier(), true, false));
				return;
		}
		super.notifyChanged(notification);
	}
	/**