Sticky scrollbars in Flex

Question

I have this situation with some scrollbars in my Flex app: If I click on a scrollbar and drag off the Flex stage, the bar stays focused. As I move and click around the page outside of Flex, the bar follows me.

Here's a video of the problem

I've tried putting an Event.MOUSE_LEAVE handler on my app but that won't fire if I mouse down and drag off the stage.

I need to unstick these puppies.