SQL 2008 Mirroring, in "restoring" state

I'm testing SQL Server 2008 mirroring with a principal, a mirror and a witness. I've gone through the examples, restoring the mirror WITH NORECOVERY. The principal says it is synchronized. But the mirror still shows it is in a "restoring..." state. Am I supposed to just leave it like that? Should I run a RESTORE WITH RECOVERY?

From stackoverflow

• Yes, it stays in a recovering state.

  The mirror isn't directly accessible--it only goes "live" when the main db goes down, and a failover occurs.