Bug 81740 Package explorer not correctly updated when deleting more than one project
M4 - create two projects X and XX - switch to workingset mode - put both into a working set - select both and delete them observe: one project is still rendered as a closed project.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/workingsets/JavaWorkingSetUpdater.java
/**
	 * {@inheritDoc}
	 */
	public boolean contains(IWorkingSet workingSet) {
		synchronized(fWorkingSets) {
			return fWorkingSets.contains(workingSet);
		}
	}
	/**
	 * {@inheritDoc}
	 */
	public void dispose() {
		synchronized(fWorkingSets) {
			fWorkingSets.clear();
		}
		JavaCore.removeElementChangedListener(this);
	}
	/**
	 * {@inheritDoc}
	 */
	public void elementChanged(ElementChangedEvent event) {
		IWorkingSet[] workingSets;
		synchronized(fWorkingSets) {
			workingSets= (IWorkingSet[])fWorkingSets.toArray(new IWorkingSet[fWorkingSets.size()]);
		}
		for (int w= 0; w < workingSets.length; w++) {
			WorkingSetDelta workingSetDelta= new WorkingSetDelta(workingSets[w]);
			processJavaDelta(workingSetDelta, event.getDelta());
			IResourceDelta[] resourceDeltas= event.getDelta().getResourceDeltas();
			if (resourceDeltas != null) {