QTreeWidget, double-clicks and assertion errors

[Byngl]

Qt 4.1.4 commercial version on Windows XP

I've attached a sample program that illustrates what is occurring.

I have two QTreeWidgets and two push buttons (add and remove). The list on the left is the 'available' list. The list on the right is the 'selected' list. As long as I use the Add/Remove buttons everything is fine. When I double-click on an item in the 'selected' list, it will be removed without incident as long as I am not removing the last remaining item. If I attempt to double-click on the last item I get:

ASSERT failure in QVector<T>::at "index out of range"