Draggables aren't visible above other elements - z-index problem?

This is probably more of a Scriptaculous question, so if this is too
off topic, let me know.

I've got several draggable items and one receiving element for
dropping the items. The dragging and the dropping works fine except
for one thing:

The draggables and the droppable are in separate divs, and for some
reason the draggables will not remain on top when I drag them outside
of their containing div. I've tried messing with z-index attributes,
but I just can't seem to get the items, when dragged, to remain on top
of the other elements.

So what I get is a draggable that disappears behind other elements as
I drag it outside of its containing div. The droppable will receive
the draggable just fine, but if the draggable isn't visible - well,
it's really no good like that.

Anyone have any suggestions on how I can troubleshoot this? Has
anyone had any similar experiences/problems with the draggables?

Try to change the parent node of draggable element when you start
dragging.
Somenthing like $(draggable).parentNode =
$(Container_for_both_draggables_and_droppables_elements) or body.

Hmm - sorry if it's obvious, but how would I do this? Is there an
onDrag type command for scriptaculous draggables?

Sorry, I'm not the best w/Javascript.