Stretch: xfce and xscreensaver

[Jerome BENOIT <sphericaltriangle@rezozer.net>]

Hello Debian Users,

I have recently upgraded my box from Jessie to Stretch.
I encountered a few little issues that I could fixed easily.
Nevertheless, so far, I failed to fixed one of them, and a very annoying one.

During Xfce sessions, at random time my screen is filled with piece
of outdated images that were created by xscreensaver.
Most of the time, these images comes with an outdated error message from xscreensaver.

Any hint to fix is is welcome.

Thanks in advance,
Jerome