This is the Thunderbird version to track an issue that has been separately reported for Firefox. In my understanding, Thunderbird doesn't use Xulrunner. If I'm right, Thunderbird requires the same patch. Please see bug 966424 for details, which also has the patch attached.
thunderbird-17.0.6-2.fc19,xulrunner-21.0-8.fc19 has been submitted as an update for Fedora 19. https://admin.fedoraproject.org/updates/thunderbird-17.0.6-2.fc19,xulrunner-21.0-8.fc19
Package thunderbird-17.0.6-2.fc19, xulrunner-21.0-8.fc19: * should fix your issue, * was pushed to the Fedora 19 testing repository, * should be available at your local mirror within two days. Update it with: # su -c 'yum update --enablerepo=updates-testing thunderbird-17.0.6-2.fc19 xulrunner-21.0-8.fc19' as soon as you are able to. Please go to the following url: https://admin.fedoraproject.org/updates/FEDORA-2013-10755/thunderbird-17.0.6-2.fc19,xulrunner-21.0-8.fc19 then log in and leave karma (feedback).
thunderbird-17.0.6-2.fc19, xulrunner-21.0-8.fc19 has been pushed to the Fedora 19 stable repository. If problems still persist, please make note of it in this bug report.