Hi Dave,

I think the best that can be done is to make use of Excel's existing
AutoComplete option (Tools|Options|Edit|Allow AutoComplete for cell
values is ticked).

You could insert 3 rows at the top of the sheet, and in each column
that you are wanting the behaviour you have described, those three top
rows could have Red in one cell, Blue in another and Green in the
third.You could then hide rows 1 to 3.
If the "Enable AutoComplete for cell values" option on the "Edit" tab
of the "Options" dialog is selected, then you should get the desired
result.

I've checked that it works in conjunction with your Validation.

Ken Johnson