title: TouchesEnded and TouchesCancelled not called
body: <p>Okay I tested the following with the tabbed application template on Xcode 4.5/iOS 6.</p>
  
  <ol>
  <li>Created a tabbed application. </li>
  <li><p>Created a UIButton subclass called SampleButton and implemented
  the following mothods:</p>
  
  <pre><code>- (void)touchesBegan:(NSSet *)touches
             withEvent:(UIEvent *)event
  {
      [super touchesBegan:touches withEvent:event];
  }
  
  - (void)touchesCancelled:(NSSet *)touches
                 withEvent:(UIEvent *)event
  {
      [super touchesCancelled:touches withEvent:event];
  }
  
  - (void) touchesMoved:(NSSet *)touches
              withEvent:(UIEvent *)event
  {
      [super touchesMoved:touches withEvent:event];
  }
  
  - (void)touchesEnded:(NSSet *)touches
             withEvent:(UIEvent *)event
  {
      [super touchesEnded:touches withEvent:event];
  }
  </code></pre></li>
  <li><p>Added this SampleButton to the first tab.</p></li>
  <li>Added breakpoints to all the touch methods.</li>
  <li>Run on device. </li>
  <li>Tested that all the touch methods are firing as expected.</li>
  <li>Now touch the SampleButton and then also press the second tab.</li>
  </ol>
  
  <p>RESULT: View switches to second tab but touchesCancelled and/or touchesEnded are never called in SampleButton. Shouldn't one or the other of those fire if the view changes while I'm touching that button? This is proving to be a huge issue because, in my app I'm playing a sound while that button is down and it never stops playing if the user switches tabs while pressing it. Seems like this used to work fine in iOS3 and iOS4.</p>