title: How to fix VoiceOver swiping behavior after stopping and restarting the app, iPhone only?
body: <p>I have a universal app on which VoiceOver is behaving strangely, but only on the iPhone. When I delete the app and reinstall on either iPhone or iPad, VoiceOver works as expected and everything is fine. But on iPhone, if I stop the app and then restart it, VoiceOver still "works" in the sense that you can tap an element and select it for the VO focus in that way; but for some reason the left-right swiping stops working - instead of changing the focus, you just hear the "clunk" sound like you get when you reach the end of a control list.</p>
  
  <p>The app is iOS-7 only. Has anybody ever encountered this problem?</p>
  
  <p>Update: I've found that if I put this line in <code>viewDidLoad</code> of my app's root view controller:</p>
  
  <pre><code>self.view.accessibilityViewIsModal = YES;
  </code></pre>
  
  <p>everything works. Anybody understand this?</p>