Just switched to the 25 August nightly of Firebird (from 6.1) and noticed that
things have slowed back down. A lot.
Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.5b) Gecko/20030825 Mozilla
on Windows 2000
Athlon XP 2100
Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.5b) Gecko/20030825
Power Mac G4
Dual processor system.
Anyway... this shows up both on Windows and OS X, so I'm betting Linux/Unix have
it too. Curiously, though, on Mac OS, having transparent or hovering windows
doesn't have much to do with it.