When I boot up, lock or switch users in Ubuntu 18.04 I have two separate login screens that I can... well, basically choose from. One is the classic Ubuntu login and the other seems to be the gdm login screen. The classic login is on tty1 and the gdm login is on tty2. I can switch between the two by using
Ctrl+Alt+Fn1-7 Please see pictures below.
When logged in, regardless of where I had logged in from (tty1 or tty2), my xorg session is running on tty2. I can confirm that by simply switching between the tty1 and tty2 terminals. This has me vexed as I was trying to implement 2FA using Google Authenticator and the two separate login screens were locking me out; I had to boot in safe mode and change the common-auth file at a root shell prompt. Basically, this is how I stumbled upon the issue. I'd like to state that when I boot up, I am presented with the Ubuntu Unity login screen (I am able to switch to tty2 and login from there). I am also presented with the Ubuntu Unity login screen when I switch users or log-off. However, when I lock the machine I am presented with the gdm login screen.
Correction: during boot, only the Ubuntu Unity login screen is available. The gdm login screen is not.
I really have no clue why this is happening. Any help would be much appreciated.