E-book : Learning Flash Media Server 3

You can get it from here.
I got it here.

Strange flex behavior

I have this function in flex.
It works correctly as it is.
But if I interchange the lines highlighted in bold,
it stops working.
strange but true.


public function playInTheMainPanel(event:MouseEvent):void{
mainVideo.source = (VideoDisplay)((Canvas)(event.currentTarget).getChildAt(0)).source;
mainVideo.stop();
mainVideo.play();
}