title: Fullscreen app in OS X with multiple windows?
body: <p>I want to make a fullscreen app that shows the background of the new space, in addition to having normal window behavior. Basically, when the user goes full screen, I want every <code>NSWindow</code> in the app to stay the same size, stay in the same position of the screen, but move to the new space. Is this possible? If so, where is the documentation for that kind of behavior?</p>
  
  <p>EDIT: I know this is now quite old, but I have just discovered <code>customWindowsToEnterFullScreenForWindow</code>. I have used it to solve the problem. The code is below, just incase anyone else is interested in doing this too.</p>
  
  <pre><code>- (NSArray*) customWindowsToEnterFullScreenForWindow:(NSWindow*)window {
      if ([window isEqualTo:self.window]) {
          return [NSArray arrayWithObjects:window, otherwindow, nil];
      }
  
      return nil;
  }
  
  - (NSArray*) customWindowsToExitFullScreenForWindow:(NSWindow*)window {
      if ([window isEqualTo:self.window]) {
          return [NSArray arrayWithObjects:window, otherwindow, nil];
      }
  
      return nil;
  }
  </code></pre>
  
  <p>These are <code>NSWindowDelegate</code> methods though, so be sure to set the window's delegate. Otherwise, it may cause some confusion.</p>