title: Unbalanced calls to begin/end appearance transitions with nib file
body: <p>In my project, I use cocos2D. My problem is, that sometimes I get the error message "Unbalanced calls to begin appearance transitions for &lt; aViewController >... The view controller wich cause the trouble is in a framework, it is a nib file, so I can't see anything of this view controller and how it is use in the framework.
  I saw onto the internet that this error is caused when two view controllers are launched at the same time, and this is, I think, my case. In fact when I have this warning when I quit a scene, and from the other menu relaunch the scene. I get a blackscreen but I heard the music of the scene, and when I try to print the opacity of a sprite, it always gives me 255.
  I read that, replace scene method remove the precedent scene and push the new one, so I would have only one scene on the screen, but in fact it looks like not...
  I tried to add (when I quit the scene, in order to put the view at the back if it is here...) :</p>
  
  <pre><code>[self setZOrder:-100];
  [self setVisible:NO];
  [self removeFromParentAndCleanup:YES];
  [[CCDirector sharedDirector] replaceScene:[CCTransitionFade transitionWithDuration:0.1 scene:[Menu scene]]];
  </code></pre>
  
  <p>But bothing looks like working. I can't get access to the view controller which cause the unbalanced transition because it is a nib file in the framework, and can't remove properly the black screen which is an old screen...</p>
  
  <p>How could I solve this problem ?</p>
  
  <p>Thank you for your help !</p>