Comment 2 for bug 71030

A few other observations, gnome-screensaver only blanks the primary monitor - the other two monitors are not blanked and continue to function normally.

Even though the primary monitor is blanked, I can still see the mouse cursor when it moves across that monitor.

I don't know if it is related, but I am also unable to run gnome-screensaver-preferences. A window flashes on the screen, but then the program exits with the following error message:

e# gnome-screensaver-preferences

(gnome-screensaver:7708): GnomeUI-WARNING **: While connecting to session manager:
Authentication Rejected, reason : None of the authentication protocols specified are supported and host-based authentication failed.
gnome-screensaver-Message: Found best visual for GL: 0x21
The program 'gnome-screensaver' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadColor (invalid Colormap parameter)'.
  (Details: serial 232 error_code 12 request_code 1 minor_code 0)

Note that the error text is the same as in the gnome-screensaver error, but the serial number is different.