I created a connection that is limited to a single database, but after connecting I see the statusbar messages update with "Building tags file for..." using DBs that are hidden.

This seems like a performance issue.

What is the MySQL version?

Version 3.23 does not hide metadata for hidden data.

jrossiter is kind of correct. We issue SHOW DATABASES to get a list of databases that needs to be used in autocomplete. Prior to v4.1, MySQL returns all the databases irrespective of whether you have access rights on the database or not.

Now if a user has selected some particular database in the connection window, we should use only those databases in rebuilding of the tag files.

I have forwarded this issue to my development team and it will be implemented in BETA 5. I will update this thread once we release BETA 5.

Specifically I was meaning 'hidden' by being listed on the Database(s) portion of the connection dialog. Hidden by the app, not by SQL permissions.