Show system information on main page only for master admin

Virtualmin master admin user 'root' have no permission to view system information on main page once the option 'Show system information to domain owners and resellers?' via Virtualmin Configuration > User interface settings is set to 'No'. Once the option has been turned on, system information on main page is visible for every Webmin users, including 'root'. I already checked whether user 'root' is a domain owner, so I can confirm that there is no domain belongs to this user. I am using Virtualmin GPL, no reseller account is available. Attached a screenshot about the dashboard. Let me know in case further details should be provided.

Operating system: Ubuntu Linux 16.04.3
Webmin version: 1.900
Usermin version: 1.751
Virtualmin version: 6.06-2
Authentic theme version: Authentic Theme 19.21

Please have a look on the issue, waiting for suggestions.

Thanks and regards, Viktor