When a draggable item completely overlaps a droppable item, there is no tolerance that will register the draggable as "over". By adding a droppable tolerance, it is possible to make this happen.

For an example of why I would want this, see http://arko.net/files/jquery_overlap/. The pieces should only be able to be dropped when they are on top of one of the marked hexes.

Here is the case which I added to the

switch (toleranceMode)

case 'overlap':
	dao = $(oDrag.helper).offset();
	dpo = oDrop.offset;
	return ( dao.top == dpo.top && dao.left == dpo.left );

I have attached the case statement as a patch against ui.droppable.js, but since I am a jQuery newbie, there's probably a better way to do it. Thanks!