Stuck trying to get Cut, Copy & Paste to work for an NSTextField? Is Select All letting you down? This should help you out.
The simplest solution you can get is to first make sure you have setup the shortcuts in the NSMenu with a shortcut command (i.e. Command + A for Select All).
Next, Control drag from the NSMenuItem to the First Responder object in the Nib. Then scroll until to find select all. By doing this you ensure that whatever item is first responder will respond to the Command + A shortcut by doing select all when it can.
You would then go and link up all your other commands the same way.