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
private CallHierarchyViewPart fPart;
    private OpenLocationAction fOpen;
    /**
     * @param parent
     */
    CallHierarchyViewer(Composite parent, CallHierarchyViewPart part) {
        super(new Tree(parent, SWT.SINGLE));
        fPart = part;
        getControl().setLayoutData(new GridData(GridData.FILL_BOTH));
        setUseHashlookup(true);
        setAutoExpandLevel(2);
        setContentProvider(new CallHierarchyContentProvider());