The new Thunderbird 5.0b1 seems to fix the problem.
ppa:mozillateam/thunderbird-next
http://launchpad.net/~mozillateam/+archive/thunderbird-next
The new Thunderbird 5.0b1 seems to fix the problem.
ppa:mozillateam /thunderbird- next
http:// launchpad. net/~mozillatea m/+archive/ thunderbird- next