Some doubts about event propagation

programming flash
1

Hello all! How are you guys?
I just joined you’re forums and I hope I don’t make any mistake. You see I am looking for an answer, the only problem is that I don’t know how to formulate the question, I will try my best though.

I made this file, test1.fla where a movieclip named mc1 contains two other mcs. Then I wrote some simple code to make the target of the event (in this case a mouse event) shrink a little.

Here’s the code I’ve used:

mc1.addEventListener(MouseEvent.MOUSE_OVER, onDown);
mc1.addEventListener(MouseEvent.MOUSE_OUT, onUp);
function onDown(evt:MouseEvent):void {
    evt.target.scaleX = 0.5;
    evt.target.scaleY = 0.5;
};
function onUp(evt:MouseEvent):void {
    evt.target.scaleX = 1;
    evt.target.scaleY = 1;
};

When I test this movie, only the selected mc that I hover is the one that shrinks, the other does not shrink (I am talking about those guys inside mc1). However I have done a similar file called test2.fla in which I replaced the nested mc’s with shapes, the code is exactly the same, but in this case it’s mc1 that shrinks, I mean no matter what shape I hover with mouse, both shrink.

I know (think so) that this is because of event propagation, but why do these two files react in a different manner? Is it becase the mc’s inside mc1 can also be a display object container, but shapes cannot? Can you guys point me out in the right path?