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
if (fHierarchyRefreshNeeded) {
			fireChange(null);
		} else {
			ArrayList changedTypes= new ArrayList();
			processDelta(event.getDelta(), changedTypes);
			if (changedTypes.size() > 0) {
				fireChange((IType[]) changedTypes.toArray(new IType[changedTypes.size()]));
			}
		}
	}
	
	/*
	 * Assume that the hierarchy is intact (no refresh needed)
	 */					
	private void processDelta(IJavaElementDelta delta, ArrayList changedTypes) {
		IJavaElement element= delta.getElement();
		switch (element.getElementType()) {
			case IJavaElement.TYPE:
				processTypeDelta((IType) element, changedTypes);
				processChildrenDelta(delta, changedTypes); 
				break;
			case IJavaElement.JAVA_MODEL:
			case IJavaElement.JAVA_PROJECT:
			case IJavaElement.PACKAGE_FRAGMENT_ROOT:
			case IJavaElement.PACKAGE_FRAGMENT:
				processChildrenDelta(delta, changedTypes);
				break;
			case IJavaElement.COMPILATION_UNIT:
				ICompilationUnit cu= (ICompilationUnit)element;
				boolean isWorkingCopyRemove= isWorkingCopyRemove(cu, delta.getKind());