In the combobox's Row Source, use a query to return the list and instead of
the original field, use something like:
Nz([OriginalField],"Available")
>I have a drop-down control that is being populated by an entire table
>(not a query). There are NULL values in the table which appear as
>blank spaces in the drop down. How can I format the drop down to put
>some static text in place of the empty space. (For example
>'Available', or 'Not Defined').