title: Mouseenter is never triggered when entering through disabled child element
body: <p>I have a gray div with a disabled checkbox in it.</p>
  
  <p><a href="http://jsfiddle.net/hFPTU/1/" rel="nofollow">http://jsfiddle.net/hFPTU/1/</a></p>
  
  <p>I also have blue div that is positioned over the gray box, but below the checkbox.</p>
  
  <p>A third div is updated with text when <code>mouseenter</code> and <code>mouseleave</code> events are triggered on the gray box.  Mouse into gray box -> "ENTER".  Mouse out of gray box -> "LEAVE"</p>
  
  <p>Everything works just as expected, except for when you enter the gray box through the disabled checkbox.</p>
  
  <ol>
  <li>Move mouse over blue box</li>
  <li>Move mouse over checkbox</li>
  <li>No Mouseenter event is triggered.</li>
  </ol>
  
  <p>Why does this happen?</p>