Does not show thread as "read" ?

[Red Sawman]

Formerly ... when I read a post and returned to the forum ... the post would then show as the open circle ... indicating  read ...

Now ... when I return to the forum ... it still shows as a closed circle ... indicating unread ...

I am returning to the forum using the "return to forum button" ... sometimes it works and most times it doesn't ...

Also ... how do I change the number of posts viewed in a forum window ... ?

Thanks,

Red