Lock screen breaks wallpaper on dual head

[Oli]

I have two screens in a Nvidia/Twinview setup. There is a single-image wallpaper centered over the joined screens.

When the lock screen shows, the wallpaper only shows on one screen (but the date/user information at the top shows on both). The aspect is preserved so this looks awful.

IMO the wallpaper *should* display over both screens, just as it does on the real desktop.

I've taken a photo (lock.jpg below) of this to give a better description.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: gnome-screensaver 3.4.0-0ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-21.34-generic 3.2.13
Uname: Linux 3.2.0-21-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.0-0ubuntu4
Architecture: amd64
Date: Wed Apr 4 10:20:58 2012
GnomeSessionIdleInhibited: No
GnomeSessionInhibitors: None
GsettingsGnomeSession:
 org.gnome.desktop.session idle-delay uint32 600
 org.gnome.desktop.session session-name 'ubuntu'
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
SourcePackage: gnome-screensaver
UpgradeStatus: Upgraded to precise on 2012-04-03 (0 days ago)
WindowManager: No value set for `/desktop/gnome/session/required_components/windowmanager'

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.