title: UISearchBar cannot become first responder after UITableView did re-appear
body: <p>I have an iPhone app for iOS8. UIPageViewController has a child view of UITableViewController, and that's where I put UISearchController.</p>
  
  <p>When the UITableViewController is presented for the first time, I have no trouble activating the search by doing</p>
  
  <pre><code>[self.searchController.searchBar becomeFirstResponder];
  </code></pre>
  
  <p>However, once the view controller gets invisible either by pushing to another table view controller, or modally presenting a UIViewController (visually masking it), the searchBar can no longer become first responder after it reappears. </p>
  
  <p>The search itself can be done by</p>
  
  <pre><code> [self.searchController setActive:YES];
  </code></pre>
  
  <p>but, there is no caret blinking this way (user has to tap inside searchBar to start typing).</p>
  
  <p>I have almost identical UITableViewController with UISearchController without the incident. So, I must be missing something, but I would like your opinion on which direction I should pay attention on solving this.</p>
  
  <p>Below is how I set the search controller.</p>
  
  <pre><code> @interface MonthTableViewController () &lt;UISearchResultsUpdating, UISearchControllerDelegate&gt;
  
   @property (nonatomic, strong) UISearchController *searchController;
  
   UITableViewController *searchController = [[UITableViewController alloc]initWithStyle:UITableViewStylePlain];
   searchController.tableView.dataSource = self;
   searchController.tableView.delegate = self;
   self.searchController = [[UISearchController alloc] initWithSearchResultsController:searchController];
   self.searchController.searchResultsUpdater = self;
   self.searchController.delegate = self;
   self.searchController.searchBar.frame = CGRectMake(self.searchController.searchBar.frame.origin.x, self.searchController.searchBar.frame.origin.y, self.searchController.searchBar.frame.size.width, 44.0);
   self.tableView.tableHeaderView = self.searchController.searchBar;
   self.definesPresentationContext = YES;
  
   // Hide search bar
   CGRect myBounds = self.tableView.bounds;
   myBounds.origin.y += self.searchController.searchBar.frame.size.height;
   _lastlyAddedTableBoundY = self.searchController.searchBar.frame.size.height;
   self.tableView.bounds = myBounds;
  </code></pre>