Basically what I want to achieve in Ubuntu Gnome is something like a customized guest account that I was able to create in Unity Desktop. I need an account that is always launched with the same preferences set up for the other account. This is a must have feature in a computer classroom. Kids like to tinker with programs, and they left them changed when going away. But a new class comes in and they need to see the default view of the program when they launch it.
I know I can install light-dm instead of gnome session manager, but it seems not appropriate. I want to find a way to do this in gnome. Please help!