Well, it seems that it was the "Notification Area" which has disappeared (probably during a bad crash on wake from sleep).
Solution for me: Add to Panel... --> "Notification Area" -- The nm-applet icon is missing or the sound icon is duplicated and the second one is dead https://bugs.launchpad.net/bugs/482684 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
