Hi Adrian,
Sorry for the monster delay...

I've implemented these behaviors in v3 b91 (will post soon):
Return key on selected row: enter editing the text column.
Tab key while editing: Allows you to navigate editable fields between columns/rows.
Return key while editing: selects next row in the same column.
Tab/Return + Shift key: reverse order.
Thanks for the patience
Mixage Software
www.mixagesoftware.com
support@mixagesoftware.com