I'm managing a site that was built in SS 2.3 (it was actually built by SS themselves a few years back... )
The login seems to have a timeout set, so that users are being logged out after a fairly short period of time.
I don't know where this is set, or if it's just a feature of SS 2.3? But basically they want to remain logged in with no time out...
You can change the session timeout value in php.ini on the server. This is about the only place to do it, although some servers may allow you to do that through the application (most don't for security reasons).
So to answer your question, it's not a feature of SS2.3.
Hope that helps, please forgive me if I've misunderstood your question.