Either I'm blinded or there is no way to change the current database except by using the terminal.
Don't worry you're not blind, the database selection will come with the next version of our Finder. The version should be released soon (2 weeks top).
Indeed, the current workaround is to open Redsmin terminal and change the database (via `select X`) from there.
Thanks for your feedback, feel free to tell us if anything else is missing!