title: MPMoviePlayerController showing black empty screen does not allow to do anything
body: <p>I am getting an a problem related to MPMoviePlayerController. </p>
  
  <ul>
  <li>Some time, When I play a video, its output is black screen only.  </li>
  <li>Got message on console <code>unexpected nil window in _UIApplicationHandleEventFromQueueEvent, _windowServerHitTestWindow: (null) MPMoviePlayerController</code>.</li>
  <li>App screen remains black even on app moved to background.</li>
  </ul>
  
  <p><strong>Code:</strong></p>
  
  <pre><code>NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
  
  NSString *videoURL = [NSString stringWithFormat:@"%@",[prefs objectForKey:@"videoURL"]];
  [self.moviePlayer setContentURL:[NSURL URLWithString:videoURL]];
  [ self.moviePlayer prepareToPlay];
  [ self.moviePlayer.view setFrame: self.view.bounds];
  [self.view addSubview:self.moviePlayer.view];
  self.moviePlayer.scalingMode = MPMovieScalingModeNone;
  [self.view addSubview:self.moviePlayer.view];
   self.moviePlayer.controlStyle = MPMovieControlStyleEmbedded;
  [self.moviePlayer setFullscreen:YES animated:YES];
  [self.moviePlayer play];
  </code></pre>
  
  <p>Any idea about it?</p>