This thread is rather old, but it seems the problem with LXDE shutdown/reboot/hibernate actions comes up again and again. After today's system update (Debian "jessie" - testing version), it happened again to me, and probably others too. Reason: new version of networkmanager requires systemd. However, as other people pointed out already, systemd breaks lxsession-logout functionality. This is because lxsession-logout detects systemd-logind and tries sending shutdown/reboot commands to dbus through logind, which won't work, as lxsession works correctly only with consolekit (see, e.g., this
thread for details).Solution
: Get rid of systemd. There are plenty of threads out there proving switching to systemd is not an easy task, and I don't think it is a good choice anyway, at least for now. This, however, will break network-manager package. Not a big deal. Just install a very good alternative, namely wicd
; you might also want to install wicd-gtk
for a graphical front-end). Then purge network-manager and all its dependencies, plus network-manager-gnome, if you have it installed too.