Comment 5 for bug 1723117

problem disappeared in Ubuntu 18.04
corrado@corrado-beta-4ott:~$ apt policy gnome-shell-extension-ubuntu-dock
gnome-shell-extension-ubuntu-dock:
  Installed: 0.8
  Candidate: 0.8
  Version table:
 *** 0.8 500
        500 http://archive.ubuntu.com/ubuntu bionic/main amd64 Packages
        500 http://archive.ubuntu.com/ubuntu bionic/main i386 Packages
        100 /var/lib/dpkg/status
corrado@corrado-beta-4ott:~$