Comment 7 for bug 765736

Is a language pack bug.
Disabling Italian Language pack from Language tab (from Add-ons menu in Thunderbird) I can stick the icon in the launcher and get the quick-list back.

The gsettings key is updated when I click "stick on launcher"

giovanni@shrimp:~$ gsettings get com.canonical.Unity.Launcher favorites
['nautilus-home.desktop', 'google-chrome.desktop', '/home/giovanni/bin/unity/CustomSSH.desktop', 'gedit.desktop', 'virtualbox-ose.desktop', 'filezilla.desktop', 'libreoffice-writer.desktop', 'libreoffice-calc.desktop', 'ubuntu-software-center.desktop', '/home/giovanni/.local/share/applications/thunderbird.desktop']
giovanni@shrimp:~$