I believe this is due to the HUD trigger being mapped to (left) Alt. Try disabling it from ccsm (compizconfig-settings-manager, desktop - unity plugin; key to show the HUD) if it changes the behaviour.
** Package changed: xserver-xorg-input-keyboard (Ubuntu) => unity (Ubuntu) ** Changed in: unity (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/986197 Title: Keyboard layout switching with combination involving Shift key is inconsistent To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/unity/+bug/986197/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs