Reproduction steps:
1) install jEdit (from http://www.jedit.org/) 2) launch thunderbird/firefox, open any page you can paste in or create a new message 3) write some text in jEdit and copy-paste it to mozilla (by ctrl+c, ctrl+v).
I can reliably reproduce it on Fedora 12/i686.
Reproduction steps:
1) install jEdit (from http:// www.jedit. org/) firefox, open any page you can paste in or create a new message
2) launch thunderbird/
3) write some text in jEdit and copy-paste it to mozilla (by ctrl+c, ctrl+v).
I can reliably reproduce it on Fedora 12/i686.