Drag'n'Drog and DBGrid -- Help!

[Delphi 3]
        I'm new to the Drag and Drop concept, so please help me
make sense of it!  I seem to be most of the way there, but I
can't figure out how to make the row in a DBGrid below the
drag cursor become the SelectedRow when the object is dropped.
[I'm trying to update a field value in the DBGrid, but the
SelectedRow doesn't change in response to the mouse-up of the
drag event, so the wrong record gets updated.]

Any suggestions about how to force the cursor to
the Mouse Coordinates would be appreciated.  [I know about
TDBGrid.MouseCoord(), but don't know how to get the cursor
to move to the coordinate's row.]  

Thanks,  Brian