There is a problem with Read Only permissions.

When you set user to be Zabbix Admin.
Add this user to group G1
Assign this group to Read Only permission on host group host_group_1 (with host1, host2 inside the group).

Then, login to the system and you will see on Dashbord two host, you can search for them etc.. but Go to Configuration tab, and there will be no host to configure.

All is ok, when you have Write permission.

What is about:

In configuration tab, when the user has read-only permission, then he should see the config (he is Zabbix Admin) but with no permission to change anything.