title: jQuery UI - draggable / droppable dataTransfer is undefined
body: <p>This is driving me mad.</p>
  
  <p>Please forgive me but I'm not going to post the full code as it is (I believe) irrelevant. The reason behind this is obviously with my code. I was getting the following error:</p>
  
  <blockquote>
    <p>draggable / droppable dataTransfer is undefined</p>
  </blockquote>
  
  <p>So I decided to copy the source from:</p>
  
  <p><a href="http://jqueryui.com/droppable/#photo-manager" rel="noreferrer">http://jqueryui.com/droppable/#photo-manager</a></p>
  
  <p>and I still get the same error.</p>
  
  <p>I am using the latest jQuery UI with all packages included.</p>
  
  <p>Does anyone know why this happens but not on the jQuery UI example?</p>
  
  <p>Regards.</p>