Hello,

it was not working for me, I mean, once lightdm installed along lightdm-gtk-greeter I could use it to login at first attempt, but then I could not use shutdown/reboot or exit session as simple user.
I found this post which has allowed me to solve it : https://dev1galaxy.org/viewtopic.php?id=2282 the solution is 3 years old but it helped me sort it out.