Mouse Leave does not fire

Hey guys, I am hoping someone has a quick answer for me on this. I am trying to handle a drag event when the cursor leaves the stage. Should be fairly simple with Event.MOUSE_LEAVE, but I am having unexpected difficulties.

with:

this.stage.addEventListener(Event.MOUSE_LEAVE,this.mouseDragReleaseHandler);

I never reach the code in mouseDragReleaseHandler

however with:

this.addEventListener(MouseEvent.MOUSE_UP,this.mouseDragStopHandler);

I do…

I am using the 3.2 version of the API, if that matters. Still haven’t updated.
Any thoughts?