Message list discussion

Timo and me currently investigate possibilities to improve the threaded-view usability. One idea by ibm research came to our mind. Timo already implemented an arc-viewer control, so we would be able to play around with this thing after the RC2 release.Maybe, this way we could get rid of the current JTreeTable message-list and replace it with something more generic. The threaded-view capabilities make this old control a pain in the ass.