The red div (#draggable_item) is marked as a draggable limited to the parent green div (#draggable_container). Dragging is limited to the y-axis.

If there is a css border on the parent element set, the dragging does not work fine. If you try to drag the item several times, it will escape from the parent element. If you disable the green border, everything works fine.

The above behaviour was observed in both MSIE 7 and FF 2.0.0.13.

Hope this description helps you to solve the problem.

Regards, Jan Matyas