I would appreciate if in the user tab there would be a tab sporting the roles the user is associated with. Likewise, I would welcome such information on a tab in the roles as well as a tab sporting all users associated with the role. The icing on the cake would be to get the role dependency information like the ones described in https://support.dbvis.com/support/discussions/topics/1000094340
Just to inform you that DbVisualizer 11.0 has been released with a few fixes related to the roles and users request.
In DbVisualizer open Help->Check for Update to run the upgrade or download from our web site.
Please let me know if I can be of further assistance with any questions you may have.
I will add this as an improvement request.
I speak of DB2 LUW. I did not check other databases.