If I had to do this without new windows (or new tabs in my case, because I'm always using a browser with that feature) I'd go crazy, er, crazier. I'd never be able to scan/read as much as I do now.

Anyway, that doesn't seem to be the problem. I've been popping new tabs like usual during this session, and everything's been fine. I think it's a time issue. Based on this afternoon's session, I'm thinking perhaps after one hour it times out and loses the read/unread info, regardless of your continued activity. (I read through everything I wanted to look at, and at the very end they started no longer appearing unread properly. It was I believe just over an hour from when I started.) I wonder if that setting can be changed anywhere?