Bug 36672 call hierarchy: Should show a progress bar
The Call Hierarchy view should show a progress bar when searching for callers/callees, allowing the user to abort the search.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/callhierarchy/CallHierarchyViewer.java
/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *   Jesper Kamstrup Linnet (eclipse@kamstrup-linnet.dk) - initial API and implementation 
 * 			(report 36180: Callers/Callees view)
 ******************************************************************************/
package org.eclipse.jdt.internal.ui.callhierarchy;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.KeyListener;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Menu;
import org.eclipse.swt.widgets.Tree;
import org.eclipse.swt.widgets.TreeItem;
import org.eclipse.jface.action.IMenuListener;
import org.eclipse.jface.action.MenuManager;
import org.eclipse.jface.viewers.IOpenListener;
import org.eclipse.jface.viewers.OpenEvent;
import org.eclipse.jface.viewers.TreeViewer;
import org.eclipse.ui.IWorkbenchPartSite;
import org.eclipse.jdt.internal.ui.IJavaHelpContextIds;
import org.eclipse.jdt.internal.ui.util.JavaUIHelp;
import org.eclipse.jdt.internal.corext.callhierarchy.MethodWrapper;
class CallHierarchyViewer extends TreeViewer {