User remains logged in

[Doc55]

In my forum, I have the session set to 900. So I expect the users that are inactive for 900 seconds to be automatically logged out. However, this is not happening.
I can log in, then close the browser, come back 4 hours later and I'm still logged in.
Is there any other setting that I need to change for the session to expire after certain time of inactivity?

[Mark.B]

The session expiring doesn’t log you out. It just means the session is expired so you no longer show online.

If you have ticked “Remember” when logging in, then next time you visit the site you will be automatically logged in. This is by design.

[Doc55]

Got it. Thanks for the clarification.