Managed Unit view only

Hi all,

I am relatively new to ARS and tried to set up a MU with explicit permission to some groups, this worked well and I have added the specific group with builtin "Managed Units View" and "Group - Read all Properties" access.
Now when I login to WEB UI with the account I cannot see anything under AD tree (OK) and MU (NOT OK). Do I have to grand permission on the Domain top level or something to make the MU groups visible for the account?

Many thanks for your help.