New comment by gc-user on void-packages repository

https://github.com/void-linux/void-packages/issues/44551#issuecomment-1609124042

Comment:
I can replicate it every time, even if the conf file only contains that line and no other. Of course, the changes only get applied after reboot. And, of course, if this line is also removed, the bug can't be noticed as the user name list to choose from is displayed.

Also, I'm talking about 

/etc/lightdm/lightdm.conf.d/50-lightdm.conf,

not 

/etc/lightdm/lightdm.conf

The latter is the official / default file, the former is the one one can / should use for modifications.

But you wrote about lxdm. I couldn't determine if you tried to replicate the issue with lxdm being activated or not.
The bug seems to be happening between xfce4ui and one of the light* packages. Having lxdm installed might interfere with that and mask the bug.

Also, if that bug only appears after updating libxfce4ui to v4.18.4 and disappears after downgrading libxfce4ui to v4.18.3, why would uninstalling and reinstalling (the same versions of) lightdm / lightdm-gtk3-greeter have any effect?

Anyway, maybe one day, if there are no updates to the light* packages in the near future, or another future update to xfce4ui doesn't revert that bug, I might have to go and check the difference between the current and the previous version of xfce4ui to see if I maybe can detect something that could affect the login screen.