In Access classic I've run the Control Wizard during Form Design, to generate a combo box record navigator. That is, the Combo Box displays a list of record identifiers and after selection, the Form displays the relevant record. The Control Wizard that makes this always worked in class and when working.
In a recent Access 2007 class, this no longer worked. Fine, I thought, they have removed the feature - maybe they haven't translated the VBA coding to Access 2007 macro coding. But wait, let's go check Google Groups.
It appears that is the record source of the Access 2007 Form is not simply a table, but an SQL string, that third option doesn't present itself. Maybe in classic Access, that was the same deal but it never hid itself from me.