

But when I reboot (or shutdown - power up), and open a new FireFox window, all of my previous windows with tabs are open! When I open a new Firefox window, I have a new session. On firefox I have not selected "Restore previous session" under the Preferences > Startup option. Nothing in the "Applications to be excluded from sessions".

Under Settings > Startup and Shutdown > Desktop Session, I have "End current session" for the leave option and "Start with an empty session" for the on login option.
