Screen content exposed although locked + no login dialogue

[marw]

Screen content is exposed although the screen is locked, and no login dialogue is accessible.

I discovered this in Google Chrome, and here is how to reproduce it:

1. Go to Google Picasa
2. Open album, select Slideshow.
3. Hit F11 to enter full screen
4. Lock screen (ctrl + alt + L) or wait for it to lock
5. Move mouse

The result:

1. Chrome as the top level window is shown with its content
2. No login dialogue is visible

To log in into Unity again, I killed chrome process - which enabled access to the login dialogue.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: gnome-screensaver 3.2.0-0ubuntu1
ProcVersionSignature: Ubuntu 3.0.0-14.23-generic-pae 3.0.9
Uname: Linux 3.0.0-14-generic-pae i686
ApportVersion: 1.23-0ubuntu4
Architecture: i386
CheckboxSubmission: de1b8d21f7c2ff6c3430ccfd5d95a676
CheckboxSystem: b1865df84255b8716d3bcc269ff410d1
Date: Fri Jan 13 16:47:54 2012
EcryptfsInUse: Yes
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release i386 (20110427.1)
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: gnome-screensaver
UpgradeStatus: Upgraded to oneiric on 2011-10-14 (91 days ago)

[Launchpad Janitor (janitor)]

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

[David Huggins-Daines (dhuggins)]

This also happens with other full screen applications - I have been noticing it with OpenNX consistently of late.

[Pander (pander)]

See also https://bugs.launchpad.net/ubuntu/+source/gnome-screensaver/+bug/1509711 and https://bugs.launchpad.net/ubuntu/+source/gnome-screensaver/+bug/1581384