title: UIStackView Hide View Animation
body: <p>In iOS 11 the behaviour of the hide animation within a <code>UIStackView</code> has changed, but I have been unable to find this documented anywhere.</p>
  
  <p><strong>iOS 10</strong></p>
  
  <p><a href="https://i.stack.imgur.com/bgmwA.gif" rel="noreferrer"><img src="https://i.stack.imgur.com/bgmwA.gif" alt="iOS 10 animation"></a></p>
  
  <p><strong>iOS 11</strong></p>
  
  <p><a href="https://i.stack.imgur.com/TwBa7.gif" rel="noreferrer"><img src="https://i.stack.imgur.com/TwBa7.gif" alt="iOS 11 animation"></a></p>
  
  <p>The code in both is this:</p>
  
  <pre><code>UIView.animate(withDuration: DiscoverHeaderView.animationDuration,
                         delay: 0.0,
                         usingSpringWithDamping: 0.9,
                         initialSpringVelocity: 1,
                         options: [],
                         animations: {
                              clear.isHidden = hideClear
                              useMyLocation.isHidden = hideLocation
                          },
                         completion: nil)
  </code></pre>
  
  <p>How do I restore the previous behaviour on iOS 11?</p>