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/TypeHierarchyLifeCycle.java
public void addChangedListener(ITypeHierarchyLifeCycleListener listener) {
		if (!fChangeListeners.contains(listener)) {
			fChangeListeners.add(listener);
		}
	}
	
	private void fireChange(IType[] changedTypes) {
		for (int i= fChangeListeners.size()-1; i>=0; i--) {
			ITypeHierarchyLifeCycleListener curr= (ITypeHierarchyLifeCycleListener) fChangeListeners.get(i);
			curr.typeHierarchyChanged(this, changedTypes);
		}
	}
		
	public void ensureRefreshedTypeHierarchy(final IJavaElement element, IRunnableContext context) throws JavaModelException {
		if (element == null || !element.exists()) {
			freeHierarchy();
			return;
		}
		boolean hierachyCreationNeeded= (fHierarchy == null || !element.equals(fInputElement));
		
		if (hierachyCreationNeeded || fHierarchyRefreshNeeded) {
			IRunnableWithProgress op= new IRunnableWithProgress() {
				public void run(IProgressMonitor pm) throws InvocationTargetException {
					try {
						doHierarchyRefresh(element, pm);
					} catch (JavaModelException e) {
						throw new InvocationTargetException(e);
					} finally {
						if (pm != null) {