>>I did two things, which appear to have taken care of the problem
>>
>>(1) There was a controlsource on the combo which referred to the actual field in the table. I replaced that with a form property.
>>
>>(2) I also did a requery on the combo as part of the "add" command button.
>>
>>In combination, these seem to have taken care of the problem.
>
>Just a thought, a combobox gets slower as you add more rows to it. That, IMO makes a combobox as a navigation tool a questionable choice. There should not be built-in limitations on the number of records your system can handle, right? :)

True, esspecially when having tables with a large number of records it does not make sense to use a combobox.

However there are also examples where it is self-evident that the number of records would be limited. For example a state or province combobox would not hold too many options and I can imagine situations where I can use this as a navigation tool for those cases.

IOW, you need to judge whether your table will possibly grow beyond reason to use a combobox.