Bug#943543: Acknowledgement (xfce4-screensaver: Black screen after unlock)

[Christoph Groth]

I filed this bug only after verifying during one night that it does not
occur with xscreensaver.  However, now I just observed it after a
suspend period of a couple of hours.  The package xfce4-screensaver
cannot be the culprit, since it is no longer installed.