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
IContributionItem item = items[i];
			if (item instanceof ActionContributionItem) {
				ActionContributionItem aci = (ActionContributionItem) item;
				String id = aci.getId();
				if (id != null && id.equals(actionId))
					return aci.getAction();
			} else if (item instanceof IMenuManager) {
				IAction found = findAction(actionId, (IMenuManager) item);
				if (found != null)
					return found;
			}
		}
		return null;
	}
	/*
	 * Action implementations for the toolbar button and preferences and about menu items
	 */
	void toolbarButtonClicked (NSControl source) {
		NSWindow window = source.window();
		Widget widget = Display.getCurrent().findWidget(window.id);
		
		if (!(widget instanceof Shell)) {
			return;
		}
		Shell shell = (Shell) widget;
		IWorkbenchWindow[] windows = PlatformUI.getWorkbench()
		.getWorkbenchWindows();
		for (int i = 0; i < windows.length; i++) {
			if (windows[i].getShell() == shell) {
				runCommand("org.eclipse.ui.ToggleCoolbarAction");