title: Half of UIButton not responding to touch events
body: <p>I have a <code>UIView</code> - which I am using as a makeshift toolbar. It contains several <code>UIButton</code>s. (Six, I think) in a horizontal row.</p>
  
  <p>The <em>fifth</em> button over will only respond to [<code>TouchUpInside</code>] events when I click the <em>left half</em> of it - whereas all the other buttons work correctly.</p>
  
  <p>I have gone crazy making sure there weren't any other views overlapping it, etc - and everything seems okay.</p>
  
  <p>Any idea of how to investigate further? Is there any way to see an "event inspector" to see where the touch messages may be going?</p>