Comment 8 for bug 965176

Sorry for considering it fixed. I shut down the system and rebooted it and now myunity icon has been substituted by a question mark icon.
Here is the output of apt-cache policy myunity:

edubuntu@edubuntu:~$ apt-cache policy myunity
myunity:
  Installato: 3.1.1-0ubuntu1
  Candidato: 3.1.1-0ubuntu1
  Tabella versione:
 *** 3.1.1-0ubuntu1 0
        500 http://archive.ubuntu.com/ubuntu/ precise/universe i386 Packages
        100 /var/lib/dpkg/status
W: Duplicate sources.list entry http://archive.ubuntu.com/ubuntu/ precise/universe i386 Packages (/var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_precise_universe_binary-i386_Packages)
W: Duplicate sources.list entry http://security.ubuntu.com/ubuntu/ precise-security/universe i386 Packages (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_precise-security_universe_binary-i386_Packages)
W: Duplicate sources.list entry http://archive.ubuntu.com/ubuntu/ precise-updates/universe i386 Packages (/var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_precise-updates_universe_binary-i386_Packages)
W: È consigliato eseguire "apt-get update" per correggere questi problemi
edubuntu@edubuntu:~$