Don't go totally blaming your system (but also don't hesitate to upgrade). I've had a lot of experts examine the problem on various OSs (it's an even bigger problem on the Mac, see the separate thread) and for every weird problem that gets reported (and there have been some weird ones) I get several on virtually identical setups that say all is fine.
Even the author of the menubar script is stumped.
The only constant has been IE (although NS users have other weirdnesses here, unrelated to the menubar). The only browser I've not had any bad reports from is NS6.1, on both Win and Mac platforms. Even then, NS has some display irregularities that can make some pages look less than their best.
It seems without trying I went and pushed the envelope. Kind of funny, considering the number of complaints I used to get about my old conservativeness. Maybe I overcompensated
Hopefully new browser patches will fix this, plus there's an upgrade for the menubar app due very soon.
I'll take this opportunity to express my gratitude for all the testers and all the suggestions (even though they haven't worked out yet). And of course our most excellent members who, bless them, think our little strand on the web is worth all this inconvenience.