Bug 81421 Closing a project with open editors leaves stale elements in Package Explorer's working set layout
I20041216-0800 Closing a project with open editors leaves stale elements in Package Explorer's working sets mode. This only affects CUs not normal resources.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/workingsets/HistoryWorkingSetUpdater.java
return fWorkingSet == workingSet;
	}
	
	public void dispose() {
		if (fTracker != null) {
			IWorkbench workbench= PlatformUI.getWorkbench();
			workbench.removeWindowListener(fTracker);
			IWorkbenchWindow[] windows= workbench.getWorkbenchWindows();
			for (int i= 0; i < windows.length; i++) {
				windows[i].removePageListener(fTracker);
				IWorkbenchPage[] pages= windows[i].getPages();
				for (int j= 0; j < pages.length; j++) {
					pages[j].removePartListener(fTracker);
				}
			}
			fTracker= null;
		}
		if (fJavaListener != null) {
			JavaCore.removeElementChangedListener(fJavaListener);
			fJavaListener= null;
		}
	}
	
	private void initListeners() {
		fTracker= new Tracker();
		IWorkbench workbench= PlatformUI.getWorkbench();
		workbench.addWindowListener(fTracker);
		IWorkbenchWindow[] windows= workbench.getWorkbenchWindows();
		for (int i= 0; i < windows.length; i++) {
			windows[i].addPageListener(fTracker);