Bug 28575 Hierarchy view updates items twice [type hierarchy]
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/typehierarchy/TypeHierarchyViewPart.java
if (!fIsVisible) {
			fNeedRefresh= true;
		}
		Display display= getDisplay();
		if (display != null) {
			display.asyncExec(new Runnable() {
				public void run() {
					if (fPagebook != null && !fPagebook.isDisposed()) {
						doTypeHierarchyChangedOnViewers(changedTypes);
					}
				}
			});
		}
	}
	
	protected void doTypeHierarchyChangedOnViewers(IType[] changedTypes) {
		if (fHierarchyLifeCycle.getHierarchy() == null || !fHierarchyLifeCycle.getHierarchy().exists()) {
			clearInput();
		} else {
			if (changedTypes == null) {
				
				try {
					fHierarchyLifeCycle.ensureRefreshedTypeHierarchy(fInputElement, new BusyIndicatorRunnableContext());
				} catch (JavaModelException e) {
					JavaPlugin.log(e.getStatus());
					clearInput();
					return;
				}
				fMethodsViewer.refresh();
				updateHierarchyViewer();