private MenuItem createSortMenu(final SortablePropertyDescriptor spd) {
final Comparator comparator = spd.getComparator();
final MenuBar sortMenu = new MenuBar(true);
sortMenu.addItem("Sort Up", new Command() {
public void execute() {
//Window.alert("Sort Up not implemented.");
final Comparator reverse = new Comparator() {
public int compare(final Object o1, final Object o2) {
return comparator.compare(o2, o1);