Hello BKR
I have a process, that sounds very similar to what you are doing and has worked for me for the last thirty plus years - so not just with Windev.
File #1 has a primary key and a field which contains the name of the field/control calling the lookup elements. File #2 has the File #1 primary key value as a foreign key, a field for descriptions, return values etc and anything else I need to do when a choice is made. A call to File#1 in the control init passing the control name to a procedure returns the primary key which is then used to fill the drop down box from file #2
In answer to your question:
To maintain the lookup list in File #2 I have a separate small button beside the drop down box which allows access to File#2 so that items can be added or removed. Apart from the obvious advantages of having a file of look ups, this approach means that the system administrator can control who can adjust the lookup list otherwise clueless users just fill them up with crap and miss- spelled duplicates
Regards
Al