title: MooTools Chained Functions Won't Execute
body: <p>I'm using MooTools and I've got the following code that I can't seem to get to execute.  I'm expecting it to increase the width of the <code>#bar</code> element to <code>50px</code>, then <code>alert()</code> with a "hi!", and then continue increasing the width of <code>#bar</code> to <code>200px</code>.  For whatever reason, it stops after "hi!" and won't continue to execute.  What's up?</p>
  
  <pre><code>var myFx = new Fx.Tween($('bar'), {
  duration: '500ms',
  transition: 'sine:out',
  link: 'chain'
  });
  
  myFx.start('width', '50').chain(
  function() { alert('hi!'); },
  function() { myFx.start('width', '200'); }
  );
  </code></pre>
  
  <p><a href="http://jsfiddle.net/nUWsU/7/" rel="nofollow">Fiddle</a>
  ​</p>