title: iOS 11 search bar jumping to top of screen
body: <p>I've got a UITableView in which I set its header to be a search bar.</p>
  
  <pre><code>tableView.tableHeaderView = searchController.searchBar
  </code></pre>
  
  <p>Everything works according to plan until you click it and it seemingly detaches from the tableView and jumps to the top of the screen. The tableView rows stay in place. Any reason it would do that in iOS 11 and not iOS 10?</p>