I notice that if I add my username to a group and logout and back in that it doesn't affect my login. I have to reboot in order for it to take. I know that I can create a new login shell (su - $USER) where it does take (for that shell), but I'm curious if there's a way to get the entire environment to reload itself that doesn't require a reboot. I'm using XFCE with LightDM as the display manager.