title: get drag object in GWT 2.4
body: <p>I heard that drag and drop feature has finally come to GWT 2.4, i know how to use it through this video <a href="http://www.youtube.com/watch?v=KEkR1ox_K10" rel="nofollow">http://www.youtube.com/watch?v=KEkR1ox_K10</a></p>
  
  <p>However, that video only show using drag and drop to transfer string. I want to get the object that is being drag, is it possible to do so? </p>