Linking browses - `Range Limit` greyed out

I am in the process of setting up a windows with three browses of related tables - but for some reason I cannot select the Range Limit * options on the third one, no matter what I try:
afbeelding
Anyone have any idea?

In the Data pad,
Set a “key” for the Browse Table.

Thank you! Sometime it’s so simple - sadly it’s also hard to find certain information sometimes :rofl: