Can dragDrop know the source chunk?

[depstein at att.net]

With text selected for dragging from a field, it seems that a dragStart handler or a mouseDown 
handler that tries to learn "the selectedChunk" will come up empty.  The dragSource tells the 
object that was dragged from, and the dropChunk tells what chunk was dropped to.  Is there 
any way to know what chunk has been dragged from?  (Applying an offset function to the 
dragData["text"] may err if the dragged text occurs more than once in the source field).

Many thanks.

David Epstein