Steps to reproduce:

1. Create a host group test_hostgroup with a subgroup test_subgroup.
2. Create a host test_host and add it to the subgroup test_subgroup.
3. Create an user group test_usergroup with read-only permission on the host group test_hostgroup and read-only permission on all the template groups.
4. Create a user test_user and add it to the user group test_usergroup.

Result:
The user test_user does not see items and problems of the host test_host.

Expected:
The user test_user should see items and problems of the host test_host.

Currently, we have to explicitly add permissions in all the subgroups of the host group, and if we create a new subgroup, we have to modify the permissions again.