title: Storyboard "show" segue doesn't work (only in one case) after updating to xcode7
body: <p>I have a simple storyboard show segue with id <code>temp</code> and I fire it from the first view controller with this line of code <code>self.performSegueWithIdentifier("temp", sender: self)</code>. </p>
  
  <p>I put a breakpoint in the <code>prepareForSegue</code> function and everything goes fine, but instead of open the destination view controller it remains on the first one, without reacting to any tap.</p>
  
  <p>I checked the ID, recreated the destination view controller and the segue, but nothing changes.</p>
  
  <p>PS: Everything was fine before updating to xcode7 and iOS9.</p>