Bug 28575 Hierarchy view updates items twice [type hierarchy]
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/typehierarchy/TypeHierarchyViewPart.java
fHierarchyLifeCycle.freeHierarchy();
		fHierarchyLifeCycle.removeChangedListener(fTypeHierarchyLifeCycleListener);
		fPaneLabelProvider.dispose();
		
		fMethodsViewer.dispose();
		
		if (fPropertyChangeListener != null) {
			JavaPlugin.getDefault().getPreferenceStore().removePropertyChangeListener(fPropertyChangeListener);
			fPropertyChangeListener= null;
		}
		
		getSite().getPage().removePartListener(fPartListener);
		if (fActionGroups != null)
			fActionGroups.dispose();
		super.dispose();
	}
			
	private Control createTypeViewerControl(Composite parent) {
		fViewerbook= new PageBook(parent, SWT.NULL);
				
		KeyListener keyListener= createKeyListener();
						
		
		TypeHierarchyViewer superTypesViewer= new SuperTypeHierarchyViewer(fViewerbook, fHierarchyLifeCycle, this);
		initializeTypesViewer(superTypesViewer, keyListener, IContextMenuConstants.TARGET_ID_SUPERTYPES_VIEW);
		
		TypeHierarchyViewer subTypesViewer= new SubTypeHierarchyViewer(fViewerbook, fHierarchyLifeCycle, this);
		initializeTypesViewer(subTypesViewer, keyListener, IContextMenuConstants.TARGET_ID_SUBTYPES_VIEW);
		
		TypeHierarchyViewer vajViewer= new TraditionalHierarchyViewer(fViewerbook, fHierarchyLifeCycle, this);