MouseEvent.DOUBLE_CLICK issues!

Do you have to perform some kind of VooDoo magic to get MouseEvent.DOUBLE_CLICK to work? here’s my code:

import flash.events.*;
box_mc.addEventListener(MouseEvent.DOUBLE_CLICK, openFolder);
function openFolder(e:MouseEvent):void {
 trace("open");
}

super simple code, just have “box_mc” on the main timeline, first frame.
thx for the feedback!