IE: drag thumb on scrollbar in sortable item tries to drag sortable item

My sortable items sometimes have scrollbars. On Chrome, this works fine, but on IE, I have issues.

On a sortable item with a scrollbar, click on the thumb and drag it to move the scrollbar, when you do a mouseup, the drag event of the sortable continues and won't release until I press the esc key.

I am currently using IE9 (9.0.8112.16421)

Thanks,

--Ed