title: popViewControllerAnimated animation is not working
body: <p>I know this is kind of repetitive question in SO, but I'm still unable to figure it out. The animation is not working when the app goes to background and then comes back up. The first time the app launchs I'm able to get the push/pop animation between the views, but once the app goes to background, it stops animating anymore.</p>
  
  <p>I have created a custom navigation controller class extending <code>UINavigationController</code> and written the <code>popViewControllerAnimated</code> method in it.</p>
  
  <pre><code>- (UIViewController *)popViewControllerAnimated:(BOOL)animated {
      UIViewController* viewController = [super popViewControllerAnimated:animated];    
      UIViewController* nextViewControler = [[self viewControllers] lastObject];
      [nextViewControler viewWillAppear:animated];    
      [viewController viewWillDisappear:animated];
      return viewController;
  }
  </code></pre>
  
  <p>Any help is appreciated.</p>