title: Strange warning dismissing modal view controller
body: <p>I'm working on iOS 6.
  My application has a standard navigation controller with embedded a CustomViewController.
  In this controller I create a modal view like this:</p>
  
  <pre><code>-(IBAction)presentModalList:(id)sender {
      UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];
      StationsListViewController *list = [storyboard instantiateViewControllerWithIdentifier:@"StationsListViewController"];
      [list setStationsData: [self.stationsData allValues]];
      [self presentModalViewController:list animated:YES];
  }
  </code></pre>
  
  <p>The modal controller show perfectly but dismissing generates a warning.
  The dismiss method in this controller is:</p>
  
  <pre><code>-(IBAction)backToMap
  {
      [self dismissModalViewControllerAnimated:YES];
  }
  </code></pre>
  
  <p>The warning generated is Warning: </p>
  
  <p><b>Attempt to dismiss from view controller &lt; UINavigationController: 0x1ed91620 > while a presentation or dismiss is in progress!</b></p>
  
  <p>Any clues about that?</p>
  
  <p>Thanks</p>