It looks like it is really related to Parallels, everyone suffering this might try following in the Parallels settings:
Settings > Shortcuts > System Shortcuts > "Send System Shortcuts" = Allways Source: http://forum.parallels.com/showpost.php?p=647684&postcount=12 ** Changed in: gnome-control-center (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1076973 Title: 3rd level keyboard assignment to Right-Alt not working as expected To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-control-center/+bug/1076973/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
