Происходит наложение кадров друг на друга

var objectoriginaldX:Number;
var objectoriginaldY:Number;
 
gprs.buttonMode = true;
gprs.addEventListener (MouseEvent.MOUSE_DOWN, pickupdObject);
gprs.addEventListener (MouseEvent.MOUSE_UP, dropdObject);
 
jsn.buttonMode = true;
jsn.addEventListener (MouseEvent.MOUSE_DOWN, pickupdObject);
jsn.addEventListener (MouseEvent.MOUSE_UP, dropdObject);
 
 
 
function pickupdObject (event:MouseEvent):void 
{
 event.target.startDrag ();
 event.target.parent.addChild (event.target);
 objectoriginaldX = event.target.x;
 objectoriginaldY = event.target.y;
 
}
 
function dropdObject (event:MouseEvent):void 
{
    event.target.stopDrag ();
    var matchingTargetName:String = "target" + event.target.name;
    var matchingTarget:DisplayObject = getChildByName (matchingTargetName);
    if(event.target.dropTarget != null && event.target.dropTarget.parent == matchingTarget)
    {
    event.target.removeEventListener(MouseEvent.MOUSE_DOWN, pickupdObject);
    event.target.removeEventListener(MouseEvent.MOUSE_UP, dropdObject);
    event.target.buttonMode=false;
    event.target.x = matchingTarget.x;
    event.target.y = matchingTarget.y;
    }
    else
    {
    event.target.x = objectoriginaldX;
    event.target.y = objectoriginaldY;
    }
}