title: UIScreenEdgePanGestureRecognizer not recognized on iPhone app running on iPad
body: <p>I have an iPhone only application that uses a UIScreenEdgePanGestureRecognizer to implement a custom interactive transition in a UINavigationController. The gesture recognizer is created and added as follows in the viewDidLoad of the UINavigationController subclass:</p>
  
  <pre><code>UIScreenEdgePanGestureRecognizer* edgeRecognizer = [[UIScreenEdgePanGestureRecognizer alloc] initWithTarget:self action:@selector(pan:)];
  edgeRecognizer.edges = UIRectEdgeLeft;
  [self.view addGestureRecognizer:edgeRecognizer];
  </code></pre>
  
  <p>When the app is run on the iPad, when I attempt to swipe to pop a view controller from the navigation stack, nothing happens in the app and I get the following console output if I start the gesture to the left of where the app window is:</p>
  
  <blockquote>
    <p>unexpected nil window in _UIApplicationHandleEventFromQueueEvent,
    _windowServerHitTestWindow: ; layer = ></p>
  </blockquote>
  
  <p>Does anyone know the reason for this and how/if I can fix this? I can't find anything so far in the documentation indicating that the edge pan gesture should not run in compatibility mode. I am testing in iOS 8.</p>
  
  <p>The gesture does work in the Simulator, but not on devices.</p>