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.edit/src/org/eclipse/e4/ui/model/application/ui/basic/provider/PartStackItemProvider.java
/**
 * Copyright (c) 2008 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *      IBM Corporation - initial API and implementation
 */
package org.eclipse.e4.ui.model.application.ui.basic.provider;
import java.util.Collection;
import java.util.List;
import org.eclipse.e4.ui.model.application.provider.UIElementsEditPlugin;
import org.eclipse.e4.ui.model.application.ui.basic.MPartStack;
import org.eclipse.e4.ui.model.application.ui.provider.GenericStackItemProvider;
import org.eclipse.emf.common.notify.AdapterFactory;
import org.eclipse.emf.common.notify.Notification;
import org.eclipse.emf.common.util.ResourceLocator;
import org.eclipse.emf.edit.provider.IEditingDomainItemProvider;
import org.eclipse.emf.edit.provider.IItemLabelProvider;
import org.eclipse.emf.edit.provider.IItemPropertyDescriptor;
import org.eclipse.emf.edit.provider.IItemPropertySource;
import org.eclipse.emf.edit.provider.IStructuredItemContentProvider;
import org.eclipse.emf.edit.provider.ITreeItemContentProvider;
/**
 * This is the item provider adapter for a {@link org.eclipse.e4.ui.model.application.ui.basic.MPartStack} object.
 * <!-- begin-user-doc -->
 * <!-- end-user-doc -->