Can't add label to list box using Control Properties

I’ve defined a list box on my form. It works perfectly. But I can only manually add a label. I’d like to do this using the Control Properties.

When I open the Control Properties of the list box, on the General tab, when I click the “…” for Label Field I see all the fields in the main table EXCEPT for the one I need.

Hello,
I have tried multiple methods to duplicate your problem but fail to do so. It would be best to post a copy of your redacted Base file.