Using debian unstable with Gnome 3 but I think this has always happened.
If I log out and then log back in again it seems the X session is restarted or in some way changed.
In any case, when I start a terminal in the second session and re attach the screen, it's no longer possible to start X apps. (message is 'Cannot open display').
Is there an environment variable I can set or command I can run so that the screen session knows the new X details, or do I always have to start a new screen session?
However, there are various other environment variables that have changed which I'd like to preserve. This page suggests a way of grabbing the environment variables when screen starts, and 'loading' them when the session is restored.
– Edd Steel Sep 15 '11 at 21:42