I was already a member of those groups. I checked that box, saved, and closed and reopened Functions Maintenance. There is still no custom code widget in the designer.
Edit: Oh, I see. I have to delete my function and recreate it as a “function with code.”
I wonder, if I use the Set Argument/Variable widget to set a variable to something there’s 0…n of like SalesOrderTableset.OrderRel.Plant, does everything downstream run once for every value? Is that how to iterate?