Comment 114 for bug 1733557

Single user desktop - steps to reproduce:
1) restart computer or log out user
2) log into user session from LightDM
3) use the gear icon menu to lock the screen
4) use the gear icon menu to switch the account
5) now we are switched into LightDM
6) log into user session again
7) use the gear icon menu to lock the screen
8) Authentication failure - Switch to greeter