Reference Selector not Populating my Data

From a Mendix newbie,

I have defined 2 entities in my Domain Model. One is named User with attributes Title (string) and Name (string). The second is named Codes_File with attributes Code (Enum) and Description (string).

I have built an input page where an administrator can build the CodesFile data by selecting the input (Code = enum, eg Title, Language, etc…) using a reference selector as a dropdown and typing in the Description. This all works perfectly, but when I create an Employee new/edit page and have the reference selector dropdown on the attribute Title in my User entity, it allows me to select the correct Title from the CodesFile, but does not populate my data with this record. How do I correct this? Do I need a microflow of sorts to ensure that this is committed to the database? If so, what and how .....

Thanx