When dragging a story to another version on planning boarrd, if there are > 12 subtasks Greenhopper doesn't move any subtasks

It works fine with 12 subtasks or less. After 12 subtasks the GH dialog tries to show pages of subtasks when dragging the story, but it fails to display any subtasks at all so the dialog just looks blank w/2 pages see http://skitch.com/cbrookins/bc3qr/planning-board

This is a big bug for us and impeding our use of Greenhopper - there is no workaround that I see