Problem switching users from plasma under lightdm

[Shai Berger <shai@platonix.com>]

Hello,

I've been using lightdm as the display manager on my Debian Testing for
a very long time, and have been quite pleased with it. But lately -- not
sure since when, I think in the last two weeks -- something broke in
the communication between Plasma and lightdm. The screen locker doesn't
show "switch user" anymore, and neither does the "Leave" part of the
launcher menu. I have the Lock/Logout plasmoid in the systray, which
always shows a "switch user" icon, and that works, but is currently the
only graphical way to switch user.

I've tried running an XFCE session and its logout window had a working
"switch user" button, so I'm guessing Plasma is the prime suspect.

Has anyone else encountered anything similar?

Thanks,
	Shai.