Bug 110998 [Problems] Remove the working set selection and switch to using global working sets
M2 We need to remove the working sets option in the filter and switch to using the current list of working sets. We should move this to a preference that says only "Use Working Sets"
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/views/markers/internal/MarkerSupportRegistry.java
* @return ProblemFilterRegistry
	 */
	public static MarkerSupportRegistry getInstance() {
		if (singleton == null) {
			synchronized (creationLock) {
				if (singleton == null)
					
					singleton = new MarkerSupportRegistry();
			}
		}
		return singleton;
	}
	private Collection registeredFilters = new ArrayList();
	private HashMap registeredProviders = new HashMap();
	private HashMap categories = new HashMap();
	private HashMap hierarchyOrders = new HashMap();
	private MarkerType rootType;
	/**
	 * Create a new instance of the receiver and read the registry.
	 */
	private MarkerSupportRegistry() {
		IExtensionTracker tracker = PlatformUI.getWorkbench()
				.getExtensionTracker();
		IExtensionPoint point = Platform.getExtensionRegistry()
				.getExtensionPoint(IDEWorkbenchPlugin.IDE_WORKBENCH,
						MARKER_SUPPORT);
		if (point == null)
			return;
		IExtension[] extensions = point.getExtensions();