Bug 257723 [Mac] Menu items "About Eclipse SDk" and "Preferences" of Top menu "Eclipse" not disable after show the dialog of "About Eclipse SDK"
bundles/org.eclipse.ui.cocoa/src/org/eclipse/ui/internal/cocoa/CocoaUIEnhancer.java
.getActiveWorkbenchWindow();
		if (activeWorkbenchWindow == null)
			return;
		
		IHandlerService commandService = (IHandlerService) activeWorkbenchWindow
				.getService(IHandlerService.class);
		if (commandService != null) {
			try {
				commandService.executeCommand(commandId, null);
			} catch (ExecutionException e) {
			} catch (NotDefinedException e) {
			} catch (NotEnabledException e) {
			} catch (NotHandledException e) {
			}
		}
	}
    /**
	 * Find the action with the given ID by recursivly crawling the provided
	 * menu manager. If the action cannot be found <code>null</code> is
	 * returned.
	 * 
	 * @param actionId
	 *            the id to search for
	 * @param manager
	 *            the manager to search
	 * @return the action or <code>null</code>
	 */
	private IAction findAction(String actionId, IMenuManager manager) {
		IContributionItem[] items = manager.getItems();
		for (int i = 0; i < items.length; i++) {