Richard,
I just downloaded the PCResale Database for this lesson (Expert 23). I was doing some exploring and trying to add products to OrderF.  When I try to create a new order in this database for an existing customer via the Add Product button at the bottom of OrderF--the button is actually part of subform OrderDetailF, at the bottom--I get the following error when I try to tab to the second product: "You cannot add or change a record because a related record is required in table 'OrderT'.
I thought we fixed this issue in previous lessons. (Was it Expert 22?  I don't recall.)
Why's it still in Expert23?  I must be missing something.
Thoughts?