Bug 317405 [Model] HandledItem should be abstract
Looks like an oversight the only real types are HandledMenuItem and HandledToolItem.
bundles/org.eclipse.e4.ui.model.workbench/src/org/eclipse/e4/ui/model/application/ui/menu/impl/MenuPackageImpl.java
* <!-- end-user-doc -->
	 * @generated
	 * @ordered
	 */
	public static final int MENU_SEPARATOR__TOOLTIP = MENU_ELEMENT__TOOLTIP;
	/**
	 * The number of structural features of the '<em>Separator</em>' class.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 * @generated
	 * @ordered
	 */
	public static final int MENU_SEPARATOR_FEATURE_COUNT = MENU_ELEMENT_FEATURE_COUNT + 0;
	/**
	 * The meta object id for the '{@link org.eclipse.e4.ui.model.application.ui.menu.impl.MenuImpl <em>Menu</em>}' class.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 * @see org.eclipse.e4.ui.model.application.ui.menu.impl.MenuImpl
	 * @see org.eclipse.e4.ui.model.application.ui.menu.impl.MenuPackageImpl#getMenu()
	 * @generated
	 */
	public static final int MENU = 5;
	/**
	 * The feature id for the '<em><b>Element Id</b></em>' attribute.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 * @generated
	 * @ordered
	 */
	public static final int MENU__ELEMENT_ID = MENU_ELEMENT__ELEMENT_ID;