I couldn't find menu option for BIND DNS Server under Webmin > Servers on a freshly installed CentOS 7.x dedicated server with Virtualmin setup script executed successfully, so I thought maybe BIND was not somehow installed by Virtualmin setup script and installed it manually via Webmin Configuration > Webmin Modules page. Unfortunately it didn't bring the menu item under the Webmin > Servers, so I tried just to append the "bind8/?xnavigation=1" in the browser's address bar and, viola, the BIND DNS Server configuration page was there intact.
So everything (including Bind) on the server is working just fine, except I can't figure out why I don't see the menu option for Bind under the Webmin > Servers. I made sure it is assigned to the Server's category on the webmin/edit_assignment.cgi?xnavigation=1 page. I'd appreciate any hints on how to resolve this issue.