Dynamic Dimension filter by UDA in Member Selector Window in Valid Intersections

Summary:

Requirement in a form: we want to display all members in the rows that have a certain UDA . Ideally, this selection should be dynamic, i.e. when new members are created with the same UDA, the rows should be extended.

Problem in "Select Members" window: I can get the members filtered in the right-hand window, but I can't get the filter "UDA:Plan(Dimension xy)" into the left-hand "Selections" window. When I click on "Results" it just inserts the static list of members. How do I get the dynamic filter into the left-hand window?

I'm grateful for any advice.