I was notified that ADxMenu does not work in IE8 beta2. Apparently, it suffers from several CSS bugs that are triggered by my menu. Nothing to actually do about it, only hope that Microsoft developers will fix these soon.
These bugs are introduced in the beta2, as the menu was working fine with beta1. New IE engine’s growing hickups, I guess.
Update: Microsoft developers fixed this in IE8. My menu is working just fine there.