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/CallHierarchyViewPart.java
*/
    private void showPage(int page) {
        if (page == PAGE_EMPTY) {
            fPagebook.showPage(fNoHierarchyShownLabel);
        } else {
            fPagebook.showPage(fHierarchyLocationSplitter);
        }
        enableActions(page != PAGE_EMPTY);
    }
    /**
     * @param b
     */
    private void enableActions(boolean enabled) {
        fLocationContextMenu.setEnabled(enabled);
         
    }
    /**
     * Restores the type hierarchy settings from a memento.
     */
    private void restoreState(IMemento memento) {
        Integer orientation= memento.getInteger(TAG_ORIENTATION);
        if (orientation != null) {
            setOrientation(orientation.intValue());
        }
        Integer callMode= memento.getInteger(TAG_CALL_MODE);
        if (callMode != null) {
            setCallMode(callMode.intValue());
        }
        Integer implementorsMode= memento.getInteger(TAG_IMPLEMENTORS_MODE);
        if (implementorsMode != null) {