Drag and drop UNDER a movie

Hi,
This might be simple, but… I don’t know, judge for yourself.
So I have this movie that I drag around my stage and check if dropped on a target using this code:

on (press) {
startDrag(this, true);
origX = this._x;
origY = this._y;
}
on (release) {
stopDrag();
var drop:String = this._droptarget;
if (drop.substr(1, 4) == ‘hole’) {
this._x = origX;
this._y = origY;
} else {
this._x = origX;
this._y = origY;
}
}
Problem is that if I drop (release mouse) while my dragged movie is UNDER another movie having a higher depth, stopDrag() has no effect. How can I solve this issue?
Thanks