Bug 189490 [CommonNavigator] Go To->Resource won't enable
I0524 1. Open the Project Explorer in the Resource perspective 2. Create a vanilla project P 3. Create a folder F 4. Create a file resource R Open the Navigate->Go To file. "Resource..." will remain disabled.
bundles/org.eclipse.ui.navigator.resources/src/org/eclipse/ui/internal/navigator/workingsets/WorkingSetsContentProvider.java
return getChildren(inputElement);
	}
	public void dispose() {
		helper = null;
		extensionStateModel.removePropertyChangeListener(rootModeListener);
	}
	public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
		if (newInput instanceof IWorkingSet) {
			IWorkingSet rootSet = (IWorkingSet) newInput;
			helper = new WorkingSetHelper(rootSet);
		}
	} 
 
	private void updateRootMode() {
		if( extensionStateModel.getBooleanProperty(SHOW_TOP_LEVEL_WORKING_SETS) )
			rootMode = WORKING_SETS;
		else 
			rootMode = PROJECTS;
	}
	protected class WorkingSetHelper {
		private final IWorkingSet workingSet;
		private final Map parents = new WeakHashMap();
		/**
		 * Create a Helper class for the given working set
		 * 
		 * @param set
		 *            The set to use to build the item to parent map.
		 */
		public WorkingSetHelper(IWorkingSet set) {
			workingSet = set;