In the old Forum format, when you selected Forum Tools and hit Mark This Forum Read, all of the highlighted (unread) threads would immediately be un-highlighted. Now they don't change until after you exit the forum. Is this a "FEATURE"?
There is a bug still there. But there also is a work around. If you click "Mark This Forum Read" from the Forum Tools menu it will look like it has done nothing but refresh the page and it will have worked.