I stand corrected. When I open a thread that I have seen before, all of the little folders are buff colored. After I open the latest, located by checking all of the dates and times, the folders for posts already read will change to white...

Additional info: When I go back to any given thread, after having looked at it already, only new posts that I have not read are buff, the old ones are all white. Now that is the way it is supposed to be all the time. Apparently the software is messed up on my first visit of the day, after that it works as designed. #$%^&*(*&^ computers!!!