Hi Ralph,

You are right - at the moment, for our Foreign Key Relation Columns - it is only making a "1 to 1" relation, so we can only limit editing of that Column type to the "single value selectBox".

But we have several users who requested this for the future, so our developers will do their best to work on adding it.

We just can't promise if or when that might be possible, but we plan on working on it.

If you wish to affect the development speed,

Please feel free to search on our suggestions page, 

 to see if someone may be already suggested this feature. If you can't see it, feel free to add your suggestion there,  and as more people vote, the feature will move higher on the priority list.

You can certainly follow our changeLog page if you'd like ( it is also available in the plugin dashboard), where we state any changes/new features/bug fixes during updates;

and our newsletter, so you're informed about new features, bug fixes, freebies, etc.