Sent Items box doesn't save sent PMs

When I send a PM it doesn't get saved in the Sent Items box. It's hard to tell whether a message was successfully sent.

Also, the Message Tracker doesn't appear to be working, with no sent messages appearing under either Read or Unread.

Have you enabled the respective options at the bottom of the compose message form?

I never saw those. It never occurred to me that it would be an option, as I've never seen forum software where PMs weren't automatically saved. Can this be made a global option?

AFAIK, no.