Thanks again for the reply!
Well, setting the width to 100% was what I had resorted to because leaving it blank wasn't working either. And, unfortunately, using "display:block" didn't work either. (Internet Explorer is so weird!) Firefox seemed to do fine with just about anything I'd throw at it though.
So, I had to go with defining an exact width. Not exactly ideal since it applies to all sub-menus, and because I'm using variable generated sub-menu link text. (It just would have been nice to have the widths adjust automatically when changes are made to the links.) But, this will have to do for now. And, it is certainly better than having the varying widths.
Hopefully Internet Explorer will catch up in terms of brain-power, or standards compliance, or something. Such a pain to always have to accommodate it.
Thanks again for the assistance!
All the best,