flash as3 first time a button pressed has no reaction

Question

I am trying to make my first game in actionscript 3 and using 3 keyframes. this is the code from my first keyframe:

gamestart.addEventListener(MouseEvent.MOUSE_DOWN, start);

function start(e:MouseEvent):void
{
gotoAndStop(2);
}

And in my second keyframe, I have a keyboard listener.

stage.addEventListener(KeyboardEvent.KEY_DOWN ,pressButton);

function pressButton(e:KeyboardEvent):void
{
trace("aaa");
}

My problem is that, after entering the second frame, the second frame doesn't seem to get "focused on", which means I still need to click it to be able to use its keyboard events. Anyway to force focus on a frame?

Answer 1

Setting stage focus is as simple this:

stage.focus = stage;