title: prepareForSegue is not called after performSegue:withIdentifier: with popover style
body: <p>I have a universal app, where I am sharing the same controller for a IPad and IPhone storyboard.
  I have put a UILongPressGestureRecognizer on a UITableView, that when a cell is pressed on iPhone it calls an action that perform a segue:</p>
  
  <pre><code>-(IBAction)showDetail:(id)sender {
      UILongPressGestureRecognizer *gesture = (UILongPressGestureRecognizer*)sender;
      if (gesture.state == UIGestureRecognizerStateBegan) {
          CGPoint p = [gesture locationInView:self.theTableView];
  
          NSIndexPath *indexPath = [self.theTableView indexPathForRowAtPoint:p];
          if (indexPath != nil) {
              [self performSegueWithIdentifier:SEGUE_DETAIL sender:indexPath];
          }
      }
  }
  </code></pre>
  
  <p>the segue is a detail view performed as a 'push'. The first thing you should notice is that the sender is an NSIndexPath, is the only way I found for passing the selected cell. Maybe there's a better solution.
  Everything works fine, in a sense that the segue is performed, and before the prepareForSegue is called too.</p>
  
  <p>However it happens that on iPad, I have changed the segue identifier to Popover.
  Now things are working in part, the segue is performed, but prepareForSegue is not called and therefore the destination view controller is not set up as it should be.</p>
  
  <p>What am I doing wrong ?</p>