Drag/drop from/to dynamic content

I have a page with 2 lists. Each list is populated with a $.get()
call. I want to drag drop from list1 to list2.
Drag/drop works but there's a visual problem : during drag, when mouse
exits list1, the dragged content disappears. Drop works but I don't
see the content over list2.
If I create the page with static lists, drag/drop works normally.
What can I do to correct the problem ?