UltraVNC

When i set idle timeout and restart computer, it works once.
if i set it to lock on idle timeout, then come back to a locked computer; when i log back in the idle timeout no longer works until I restart computer.

I tried setting the regestry IdleTimout key to 300 i.e 5 minutes.
but it doesn't seem to disconnect session

Right now a person is able to login to ultravnc and see the person's session that is logged in.
does anyone know how to set ultravnc so that only one person can login at a time.

I am trying to make it so only one person can login at a time.
right now more than one person can login.
so if you tell me the boxes you have checked, maybe we can solve eachothers problems