In Netscape 4.x, if there are any unread mails in a folder, that folder will be bold. If the folder is collapesed, its parent will be bold and so on. This really helps when user has deep multi-level folders with message filter.
However, it is missing in Netscape 6 (or did I do something wrong?). This sounds like a cosmetic problem but I think it is serious usability.
