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
* <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 * @generated
	 */
	private EClass toolBarContributionEClass = null;
	/**
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 * @generated
	 */
	private EClass toolBarContributionsEClass = null;
	/**
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 * @generated
	 */
	private EClass trimContributionEClass = null;
	/**
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 * @generated
	 */
	private EClass trimContributionsEClass = null;
	/**
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 * @generated
	 */
	private EEnum itemTypeEEnum = null;
	/**