You have been subscribed to a public bug: Some apps (e.g. TuxPaint, but there are others, I think notably ones that run in full screen) prevent the desktop from locking.
Only once you close those apps or windows does the screen lock (or does it come up at any rate). This is something that has bugged me (and therefore I think it qualifies as a bug) on other distros, e.g. Mint as well. ProblemType: Bug DistroRelease: Ubuntu 13.04 Package: lightdm 1.6.0-0ubuntu2.1 ProcVersionSignature: Ubuntu 3.8.0-19.30-generic 3.8.8 Uname: Linux 3.8.0-19-generic x86_64 ApportVersion: 2.9.2-0ubuntu8 Architecture: amd64 Date: Tue May 7 16:29:03 2013 InstallationDate: Installed on 2013-05-03 (3 days ago) InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424) MarkForUpload: True ProcEnviron: LANGUAGE=en_US:en PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: lightdm UpgradeStatus: No upgrade log present (probably fresh install) ** Affects: gnome-settings-daemon (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug raring -- Some apps prevent the screen from locking https://bugs.launchpad.net/bugs/1177405 You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gnome-settings-daemon in Ubuntu. -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs