Top most cell address, if selection is made BOTTOM RIGHT to TOP LEFT

I'm trying to position a form relative to a selection.
The line below works fine if I select in the typical manner of TOP LEFT to BOTTOM RIGHT.
But if I select BOTTOM RIGHT to TOP LEFT: I get the form relative to bottom-right cell instead of the top-left.
What will give the top-left cell address?

ActiveCell.Offset(0, 0).top