title: UISearchController searchResultsController disappears when searchbar text is empty
body: <p>I have a UISearchController that displays it's searchResultsController (which is another view controller) when the searchbar is tapped. I do this using this UISearchController delegate method:</p>
  
  <pre><code>-(void)presentSearchController:(UISearchController *)searchController {
  
      dispatch_async(dispatch_get_main_queue(), ^{
          searchController.searchResultsController.view.hidden = NO;
      });
  }
  </code></pre>
  
  <p>However, any time the searchbar's text is empty, whether by manually deleting all text or tapping the little x button, that searchResultsController view is disappearing until I start typing text again. Any ideas why this may be happening? Is there another method or delegate method that is being triggered when searchbar.text is empty?</p>