Previous user's session/desktop environment selected by default

[JoshH100]

After a user logs out, the session/desktop environment they were using is preselected on the greeter page even though this behavior is not indicated to the user (the session name is hidden and not all DE have unique icons). This a serious problem in educational environments since if a user uses a tiling window manager such as i3 , subsequent users accidently log into an i3 session and don't know how to use it. Additionally, if you select a different session/DE then enter an incorrect password, the selected session reverts back to the previous users session.

I determined that lightdm is remembering the previous session in "/var/lib/lightdm/.cache/lightdm-gtk-greeter/state". A workaround for now is to have script run on user logoff (session-cleanup-script in lightdm config) that deletes this file.

While investigating this problem I attempted to use the user-session option in lightdm.conf but appears to have no effect on this behavior.

Archlinux linux 4.12.
Lightdm 1.22
Lightdm-gtk-greeter 2.0.2

I will also mention that this environment is using ldap, NFS home folders, etc.