[flexcoders] PopUpManager.removePopUp() not actually removing pop ups

[ben.clinkinbeard]

I am seeing behavior where pop ups seem to just be getting hidden by
removePopUp(), resulting in a growing stack of them each time a new
one is added. I create the pop up like this:

var p:IFlexDisplayObject = new FailurePopUp("Error msg");
PopUpManager.addPopUp(p, model.mainAppCanvas, true);
PopUpManager.centerPopUp(p);

and removing it like this:

PopUpManager.removePopUp(this);

No idea what is going on. Any help is greatly appreciated.

Thanks,
Ben