Описание тега nsmenuitem

The NSMenuItem class defines objects that are used as command items in menus. Additionally, the NSMenuItem class also includes some private functionality needed to maintain binary compatibility with other components of Cocoa. Because of this fact, you cannot replace the NSMenuItem class with a different class. You may, however, subclass NSMenuItem if necessary.

Prior to Mac OS X v10.5, NSMenuItem conformed to the following protocols: NSCopying, NSCoding), and NSValidatedUserInterfaceItem.

https://developer.apple.com/library/mac/#documentation/Cocoa/Reference/ApplicationKit/Classes/NSMenuItem_Class/Reference/Reference.html