title: UIView transitionFromView not animating in container
body: <p>I'm using UIView transitionFromView to flip between two views. I'm currently doing the following in a UIView subclass:</p>
  
  <pre><code>UIImageView *imgView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"img.png"]];
  
  imgView.frame = CGRectMake(0, 0, 100, 100);
  
  UIView *detailView = [[UIView alloc] initWithFrame:imgView.frame];
  detailView.backgroundColor = [UIColor redColor];
  
  detailView.frame = imgView.frame;
  
  [self addSubview:imgView];
  
  [UIView transitionFromView:imgView toView:detailView duration:1.0 
                     options:UIViewAnimationOptionTransitionFlipFromLeft
                  completion:^(BOOL finished){
  
                  }
   ]; 
  </code></pre>
  
  <p>This works as expected. The transition performs as it should. The issue is that I need the transition to take place in a subview of the view that the previous code is contained within. So, I put everything in a container and try to animate that:</p>
  
  <pre><code>UIImageView *imgView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"img.png"]];
  
  imgView.frame = CGRectMake(0, 0, 100, 100);
  
  UIView *container = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 500, 500)];
  UIView *detailView = [[UIView alloc] initWithFrame:imgView.frame];
  detailView.backgroundColor = [UIColor redColor];
  
  detailView.frame = imgView.frame;
  
  [container addSubview:imgView];
  
  [self addSubview:container];
  
  [UIView transitionFromView:imgView toView:detailView duration:1.0 
                     options:UIViewAnimationOptionTransitionFlipFromLeft
                  completion:^(BOOL finished){
  
                  }
   ]; 
  </code></pre>
  
  <p>But in this case, the animation doesn't run. Instead, I only see the final result without the transition. Can anyone help me figure out how the two cases differ?</p>
  
  <p>The same problem is described here, but I don't feel the existing 'solution' is sufficient to fully describe this behavior.
  <a href="https://stackoverflow.com/questions/3602434/transition-behavior-using-transitionfromview-and-transitionwithview">Transition behavior using transitionFromView and transitionWithView</a></p>