This same thing happens to me sometimes. Rather rarely, really. But I'll go to Preferences, Browser -- and the words at top, "Preferred Web Browser," are very rapidly moving left-right-left-right-left.... It looks really bizarre. I think if I close and re-launch KoLmafia it always stops doing that; though I'm sure I've seen it stop... ah, I believe when I have typed something into the "Browser:" field. I've seen this... I think for over two years now. Like I said, very rare. At least two different computers in many versions of KoLmafia. Could have been 3 or 4 computers -- I'm not sure. They've all had Windows XP SP3. I use ... I guess you'd call 'em "full versions," usually. Almost never daily builds. Freaky deaky.