title: How to tell when a jQuery UI sortable element is moved and in an invalid state
body: <p>I have two connect sortable lists.  I want to fire an event when an item is moved away from it's current list but NOT into the other connected list or when the item is being sorted.  Anyone know how to do that?</p>
  
  <p>What I'm going for here is to have the user remove an item by dragging it away from the list.</p>