Drag & Drop refinement

Hi all--
I'm having a problem refining a drag & drop exercise. I'm using

e.target.startDrag(true);
e.target.parent.addChild(e.target);

to bring the current dragged item on top of others, but the problem i have is that when i complete the d&d exercise and press the back or next button to move to the previous/next frame in the main timeline, the dragged pieces remain in the display. Is there a better way to bring the current piece to the top without adding a child object?
Any help/guidance is appreciated. (see FLA attached)

Flash CS5/AS3

thanks!

Help? ... somebody has to have some idea. It seems like there should be a simple programmatic solution to this...