Bug 32384 Cannot open type hierarchy after a cancel
JUnit setup 1) open the type hierarchy on TestCase 2) press F4 on Object 3) cancel in progress bar 4) press F4 on Object again ->nothing happens
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/typehierarchy/TypeHierarchyViewPart.java
processOutstandingEvents();
		fInputElement= inputElement;
		if (fInputElement == null) {	
			clearInput();
		} else {
			try {
				fHierarchyLifeCycle.ensureRefreshedTypeHierarchy(fInputElement, getSite().getWorkbenchWindow());
			} catch (JavaModelException e) {
				JavaPlugin.log(e);
				clearInput();
				return;
			}
				
			if (inputElement.getElementType() != IJavaElement.TYPE) {
				setView(VIEW_ID_TYPE);
			}
			
			setMemberFilter(null);
			fIsEnableMemberFilter= false;
			if (!fInputElement.equals(prevInput)) {
				updateHierarchyViewer(true);
			}
			IType root= getSelectableType(fInputElement);
			internalSelectType(root, true);
			updateMethodViewer(root);
			updateToolbarButtons();