title: Using jquery ui sortable for merging two ordered list of items into third
body: <p>Having two lists<code>[A,B,C,D]</code> and <code>[1,2,3,4]</code>, I want to provide a user interface for merging them into a new list. In the new list the original order of each list should be maintained. For example any of <code>[A,1,B,2,C,3,D,4]</code>or <code>[A,B,C,D,1,2,3,4]</code>or <code>[A,B,1,C,2,3,4,D]</code>are OK. But <code>[B,A,1,2,3,4,C,D]</code> is not accepted, due to <code>B</code> coming before <code>A</code>.</p>
  
  <p>jQuery UI sortable seems to be a good starting point. But maintaining the original order is not supported (Of course the meaning of sortable is in contrast with my requirement. But the user interface supported with sortable, is very similar to my final goal.)</p>
  
  <p>I think handling receive event and canceling the sort when the order is not maintained, could be the solution. But could not found how to cancel or undo the drag, when receive is complete.</p>
  
  <p>Thanks in advance</p>