i figured out the problem, it caused because i set the switch button shift+alt instead of alt+shift this is caused the problem
-- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-screensaver in Ubuntu. https://bugs.launchpad.net/bugs/1303340 Title: when i press two keys for switching languages, the switching not work until i press them together exactly at the same time Status in “gnome-screensaver” package in Ubuntu: New Bug description: when i press two keys for switching languages, the switching not work until i press them together exactly at the same time in ubuntu 13.10 with latest updates To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-screensaver/+bug/1303340/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
