ActionScript 3.0 :: Mouse Events Lost In UIComponent?

I have an AS 3 class that extends UIComponent. In that class I dynamically add several sprites, that are also AS 3 classes that
extend from Sprite.So, in my UIComponent extended class, I added these listeners:

this.addEventListener(MouseEvent.MOUSE_DOWN,mouseDownHandler);
this.addEventListener(MouseEvent.MOUSE_MOVE,onMouseMoveHandler);
this.addEventListener(MouseEvent.MOUSE_UP,mouseUpHandler);

I added trace messages inside each of these event handler functions. The problem is that, whenever I try to dispatch these events starting from one of the children sprites from the UIComponent (let's say I click one of the sprites and the mouseDown event starts) the sequence works perfect. However when I try to do the same in the "blank" area of the UIComponent (which is just a

graphics.beginFill(0xffffff);
graphics.drawRect(0,0,this.width,this.height);
.graphics.endFill();) nothing happens. The events are never
"listen" by the UIComponent.

Actually if I run the app and click on the white area, the trace messages are ok, it triggers the mouseDown event, but only one time. I a click again, nothing happens.I tried adding another sprite, to have this one holding all the other sprites, and tried to add the listeners to it...same effect. I can't get that UIComponent to listen and react, only it's children sprites...

What I'm trying to implement at the end is a multiple drag selection of the children items of the UIComponent, but I have to be able to start the drag selection from any point in the screen.