Tried everything I can think of and it looks good right up until the new
field is displayed
A Lookup Field *IS* an Autonumber. That basic fact is concealed from your view
by the combo box.
See
http://www.mvps.org/access/lookupfields.htm for a critique of what many of
us consider a misfeature.
Solution: don't use Lookup fields. They are *never* necessary; you can put a
Combo Box on a Form to edit the data (storing the number, displaying
human-meaningful text), and you should never be editing data in table
datasheets in any case.
John W. Vinson [MVP]
