Where to implement methods for menu item that is not window dependent (Cocoa OSX

I currently implement most of the functions for my mainMenu in a NSWindowController subclass, this works fine for most functions but I would like to be abl开发者_开发百科e to use some menu items when no Window is selected. Where would be the best place to implement and validate these kind of menu items?

I would put those in my NSApplication delegate.