Rated 5 out of 5 stars

per Mateng el gen. 26, 2011 · enllaç permanent

There is a prerelease of v. 0.8 (0.8pre2) of Contacts Sidebar that works fine with my Thunderbird 3.1.1
http://extensions.sanjer.nl/index.php?page=tb_cs_prerelease

Hope this helps.