All I know is that if I need to scroll back to read something, it's frustrating to have the window scroll me to a newly received message. Or, in the case of public chat, a message doesn't even have to be directed at me. Stuff like:

- Public chat where I've scrolled back to read something, and the window keeps scrolling me back to current messages, which can happen once every couple of seconds, causing me to then scroll back to what I wanted to read, then get pulled back to incoming text, etc., etc.

- Dungeon groups where I've scrolled back to catch something important that was said (while keeping up with the group) only to have my text scrolled back because someone said, "OK".

I prefer my scrolled-back text to stay where I put it, regardless of incoming messages or text. The tab should blink or gain an icon upon new text received - like virtually all other notifications on the planet - not rip you away from what you're reading to display new incoming info.

Heck, this could even be optional. 'Don't adjust my chat scrolls', check the box, EZPZ.