@Ilia, why is search on the Virtualmin menu not returning Webmin module results? That doesn’t make sense. (When you search for fail2ban on the Webmin menu search box, it returns the fail2ban module, as expected. I’ve confirmed this behavior.)
It doesn’t seem to be needed to have it returned in Virtualmin, as Virtualmin is a separate module, and should have separate results. Also, it makes no sense to search for it using Webmin (server) search because you would get fail2ban on the autocomplete as you start typing. Besides we have favorites for managing quicker access and configurable hotkeys for super quick access to any module.
Authentic Theme is now the default theme in Webmin, the magic search box is a feature of Authentic Theme. Older themes had search, but it was implemented differently, and without the auto-complete features, the built-in shell escape feature, and a bunch of other magic that the search box can do.