It'd be very useful if you could scroll the messages window from the upper, search results window. The ideal keybinding would be the space bar as in many mail/news readers, where you can scroll the message window while in the message list window.
It would be doubly cool if hitting space when at the end of a day's messages took you to the next day (in the mail/news reader world, once you reach the end of a message, you go to the next one).
I just switched to Adium from Proteus and I have to say I really like it. The cool history browser is just one of the many nice touches.
Thanks!