title: Cannot seem to setEnabled:NO on NSMenuItem
body: <p>I have subclassed <code>NSMenu</code> and connected a bunch of <code>NSMenuItem</code>'s via Interface Builder. I have tested via the debugger to see that they really get initialized.</p>
  
  <p>The menu is set to not auto enable items. Still when I set any of my NSMenuItem's to <code>[myMenuItem setEnabled:NO]</code> they continue to be enabled. Even if I call <code>[self update]</code> from within the NSMenu subclass.</p>
  
  <p>What am I missing?</p>