NSPopUpButton enabling

[Riccardo Mottola]

Hello,

I have noticed that the items in a pop-up button remain disabled if the
button is not connected to an action. Not only is this limiting because an
action is not the only way to track the status of a op up button, but also
it differs from the behavior of macos-x, so limiting portability. Gregory
(thanks) took the time to check behavior on OpenStep and it agrees with
macos-x, so I would say it is a gnsutep bug. Maybe someone solevs this
immediatly or has something to reply to. Otherwise I'll file a bug report.

-Riccardo