title: What is the event in cocoa for NSWindow that tells that NSWindow is now displayed after first run?
body: <p>I need to show a sheet dialog soon after the main window has been shown after first run. If I do it in the init or awake from nib , it does not seem to work right (sheet show as window detached from main window if I do it in the init method). I guess I have to show sheet once the parent window has shown. I have an appcontroller class which has a window pointer. So I guess I need to register as a delegate or something with window ? and implement some method to receive that call ?
  Thanks, </p>