ActionScript 3.0 :: Event Added To Stage Dispatched Twice

I have this slight problem with the event ADDED_TO_STAGE. The listener is launched twice so I figured the event is dispatched twice.

Here is my .fla code :
var section:SectionStructure = new SectionStructure("xml/list.xml")
addChild(section)

The Section Structure code :
[...]
mainHolder = new MovieClip;
mainHolder.addEventListener(Event.ADDED_TO_STAGE, displayObjects);
addChild(mainHolder);
} private function displayObjects(pEvent:Event):void {
mainHolder.addChild(sectionMenu);
}
[Code] .....

The output panel displays "test A" once and "test B" twice. I fixed the problem by adding this little line on the opening of the function createButtons :
menuHolder.removeEventListener(Event.ADDED_TO_STAGE, createButtons);
I read here and there that the event ADDED_TO_STAGE is dispatched when children are added but my problem remains even when I comment everything below this line :
trace("test B");