title: dismissViewControllerAnimated completion block is not called
body: <p>I'm trying to dismiss a view controller like this:</p>
  
  <pre><code>[composeViewController dismissViewControllerAnimated:YES completion:^{
  
      NSLog(@"Hello"); // Never outputted
  }];
  </code></pre>
  
  <p>The view controller is dismissed, but for some reason the completion block is never called.</p>
  
  <p>I have never had any issues with completion block not being called with other view controllers.</p>
  
  <p>This view controller is "special" though, because it's added as a child view controller (which I have not worked with previously in my app). Does this impose any side effects why the completion block is not called?</p>
  
  <p>It's added like this: </p>
  
  <pre><code>UIViewController *rootVC = [UIApplication sharedApplication].delegate.window.rootViewController;
  [rootVC addChildViewController:self];
  [rootVC.view addSubview:self.view];
  [self didMoveToParentViewController:rootVC];
  </code></pre>