Whilst investigating bug 937611, I enabled the on-screen keyboard. However, I subsequently switched if off via "System Settings" -> "Universal Access" -> Typing tab -> "Typing Assistant".
As expected, the keyboard no longer displays on the desktop but when the screen locks automatically or is locked manually, the on-screen keyboard is displayed again.
ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: gnome-screensaver 3.2.1-0ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-16.25-generic-pae 3.2.6
Uname: Linux 3.2.0-16-generic-pae i686
NonfreeKernelModules: nvidia
ApportVersion: 1.93-0ubuntu2
Architecture: i386
Date: Tue Feb 28 10:28:11 2012
GnomeSessionIdleInhibited: No
GnomeSessionInhibitors: None
GsettingsGnomeSession:
org.gnome.desktop.session idle-delay uint32 600
org.gnome.desktop.session session-name 'ubuntu'
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release i386 (20101007)
ProcEnviron:
TERM=xterm
PATH=(custom, user)
LANG=en_GB.UTF-8
SHELL=/bin/bash
SourcePackage: gnome-screensaver
UpgradeStatus: Upgraded to precise on 2012-01-12 (46 days ago)
WindowManager: No value set for `/desktop/gnome/session/required_components/windowmanager'
Status changed to 'Confirmed' because the bug affects multiple users.