Session duration when the user is not active

Hello,

I wonder about the session duration in Keycloak when the user is not active (authenticated user to a resource application that is using KC). Namely, the parameter “SSO Session Idle” should regulate that. But what I have noticed is that after this time exceeds (“SSO Session Idle”), the tokens are invalidated but the session can be revoked by reloading the page (the related session record still exists in KC). This can be done within certain amount of time which is a mystery (unclear) to me. After that time, the session is invalidated in KC, and when I reload the page, it redirects me to the login page as expected.

My question would be: can I really control the time span between “SSO Session Idle” and the time of the complete vanishing of the session in KC when the user is not active?
Or is it something that is internal to KC, that can not be customised?

Thanks,
Konstantin