Bug 114496 [working sets] working sets: counter-intuitive hiding of resource sets
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/workingsets/WorkingSetConfigurationDialog.java
* Overrides method in Dialog
	 * 
	 * @see org.eclipse.jface.dialogs.Dialog#open()
	 */
	public int open() {
		fAddedWorkingSets= new ArrayList();
		fRemovedWorkingSets= new ArrayList();
		fEditedWorkingSets= new HashMap();
		fRemovedMRUWorkingSets= new ArrayList();
		return super.open();
	}
	/**
	 * Removes the selected working sets from the workbench.
	 */
	private void removeSelectedWorkingSets() {
		ISelection selection= fTableViewer.getSelection();
		if (selection instanceof IStructuredSelection) {
			IWorkingSetManager manager= PlatformUI.getWorkbench().getWorkingSetManager();
			Iterator iter= ((IStructuredSelection)selection).iterator();
			while (iter.hasNext()) {
				IWorkingSet workingSet= (IWorkingSet)iter.next();
				if (fAddedWorkingSets.contains(workingSet)) {
					fAddedWorkingSets.remove(workingSet);
				} else {
					IWorkingSet[] recentWorkingSets= manager.getRecentWorkingSets();
					for (int i= 0; i < recentWorkingSets.length; i++) {
						if (workingSet.equals(recentWorkingSets[i])) {
							fRemovedMRUWorkingSets.add(workingSet);
							break;
						}