Drag and Drop onto iFrame

Is it possible to drag an element onto an iframe and drop it?
Presently, it appears that the element will drag to just outside the
bounds of the iframe.
I've tried overlaying the iframe with a transparent div, but it does
not work.
This is incredibly frustrating. The drop event works, kind of, if
drop onto the overlay and then immediately mouse out of it.
Any help would be appreciated!!!