Comment # 14 on bug 1101393 from Stanislav Brabec

I just debugged both problems.

The problem in the comment 0 is caused by the logic of the suspend process:

When system goes to sleep, xfce4-power-manager calls "xscreensaver-command
-lock". But it does not wait for finishing of the lock. xscreensaver itself
uses timer that does not use real time, so the process initiates the lock and
then it goes to suspend. But the system goes to sleep even before xscreensaver
is able to finish the lock.

Proposed fix:
Either "xscreensaver-command -lock" will return after finishing the fade, or
add -sync option that will return after finishing the command, eventually also
add -skip-fade.

Problem in the comment 11 (lock before confirming the password) is caused by
xfce4-power-manager. xfce4-power-manager calls xscreensaver-command -lock
before verifying that the hibernation can be finished.