I have finally been able to spend some time to dig into this more. After
much trial and error, I ran xfce-power-manager from the command line
(xfce4-power-manager --debug --no-daemon), and I realized the following
message is being displayed over and over:
TRACE[xfpm-inhibit.c:357] xfpm_inhibit_un_
** Description changed:
I recently upgraded to kernel 4.2.0-36-generic, and since then light-
locker doesn't work anymore. However long I leave my machine on, it
never locks.
I played around with the power management settings, to no avail.
I believe (such is my theory) that this is