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/basic/provider/WindowItemProvider.java
* <!-- end-user-doc -->
	 * @generated
	 */
	@Override
	public void notifyChanged(Notification notification) {
		updateChildren(notification);
		switch (notification.getFeatureID(MWindow.class)) {
			case BasicPackageImpl.WINDOW__LABEL:
			case BasicPackageImpl.WINDOW__ICON_URI:
			case BasicPackageImpl.WINDOW__TOOLTIP:
			case BasicPackageImpl.WINDOW__CONTEXT:
			case BasicPackageImpl.WINDOW__VARIABLES:
			case BasicPackageImpl.WINDOW__BINDING_CONTEXTS:
			case BasicPackageImpl.WINDOW__X:
			case BasicPackageImpl.WINDOW__Y:
			case BasicPackageImpl.WINDOW__WIDTH:
			case BasicPackageImpl.WINDOW__HEIGHT:
				fireNotifyChanged(new ViewerNotification(notification, notification.getNotifier(), false, true));
				return;
			case BasicPackageImpl.WINDOW__PROPERTIES:
			case BasicPackageImpl.WINDOW__HANDLERS:
			case BasicPackageImpl.WINDOW__MAIN_MENU:
			case BasicPackageImpl.WINDOW__WINDOWS:
			case BasicPackageImpl.WINDOW__SHARED_ELEMENTS:
				fireNotifyChanged(new ViewerNotification(notification, notification.getNotifier(), true, false));
				return;
		}
		super.notifyChanged(notification);
	}
	/**