Icon to select user

PQ version: 9.5.5
Document: Test Sesstion - field "Responsibility".
I'm looking for setting cause to display icon "select" in field "Responsibility (picture 1 attached).

I checked 2 different profiles (on one it is working on another one does not) - for clarification ("DEVELOPER" profile is not working, "TEAM LEAD" profile is working)
They are practically identical, both users belongs to the same organization.
Both are added to the project.

Funny is, if I change profile of user inside project assignment from DEVELOPER to TEAM_LEAD it is working.... so for me looks like access rights "project dependent" but their settings (both profiles) are very much identical.
 

Both profiles have this option turned on and both have access to forms "Users" and "Resources". There must be something more becasue still not working.
Is there any specific form must be checked ?