acording to bug #52275, it's security vulnerability.
** Bug 52275 has been marked a duplicate of this bug ** Bug 47612 has been marked a duplicate of this bug ** This bug has been flagged as a security issue -- gnome-screensaver activates while playing SDL games https://launchpad.net/bugs/32457 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
