Just a heads up, I don't expect you to support third party beta or prerelease software, but in latest Minefield/Firefox (http://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/latest-trunk/) the middle clicking the title bar doesn't work at all, I guess they've change the way the title bar is rendered or programmed, anyway these changes will be finding their way into the Firefox 4 final release.
Once Firefox 4 goes into the RC releases, I'll start testing it. Too many things change between betas in Firefox right now, I'd just be chasing ghosts.
