title: Animating two UIView subviews at the same time does not work
body: <p>For some reason i am not able two animate two subviews postion. I have wrote the following</p>
  
  <pre><code>[self addChildViewController:self.photosViewController];
  [self.photosViewController.view setFrame:CGRectMake(0, -self.view.frame.size.height,    self.view.frame.size.width, self.view.frame.size.height)];
  
  [self.view addSubview:self.photosViewController.view];
  
  [UIView animateWithDuration:1 delay:0
                          options:UIViewAnimationOptionCurveEaseIn
                       animations:^{
  
                           [self.stepsView setFrame:CGRectMake(0, self.view.frame.size.height, self.view.frame.size.width, self.view.frame.size.height)];
                           [self.photosViewController.view setFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
                       }
                       completion:^(BOOL finished) {
                           if (finished) {
  
                               button.tag = 0;
                           }
                       }];
  </code></pre>
  
  <p><code>self.stepsView</code> is an <code>IBOutlet</code> <code>UIView</code> and <code>self.photosViewController.view</code> is an child view controllers view that has been added to the view.</p>
  
  <p>With the current code only the <code>self.PhotosViewController.view</code> animates. However if i comment out the line where i add the child view controllers view as a <code>subview</code> then the <code>self.stepsView</code> animates correctly.</p>
  
  <p>Even if i add the child view controller and its view before this method is called the same error happens.</p>
  
  <p>Need help as i ran in to this a couple of months back with another app and had to do a dirty hack to get around it and now want to solve this.</p>
  
  <p>Thanks</p>