It would be cool if I could mark all the topics as read. Every time I visit the forum, all the unread topics are still orange. -_-;; It's a problem I hadn't before.
phpBB 2 was aware of your current session and your previous session. Any post older than the start of your previous session was deemed read. New phpBB is more accurate about this.
What does "Mark forums read" on the main page do?
Yeah, I like the new behavior better. In the old forum, sometimes I didn't have time to read all new messages in the same session and because of that I would miss some of them, since they weren't marked as new anymore the next time I opened the forum.
Now, I can read all the messages of my interest, taking as much time as needed, and once I know that only the topics I don't care about have new messages I click the "Mark forums read" option to clear everything.
I think he may be referring to the fact that under "View unread posts", if you click on the post subject/thread name itself it does not mark the thread as read -- instead, you have to click on the last page number shown under the post subject/thread name to get that to happen. (Or in the case there's been multiple pages of posts since your last visit, you have to visit all of them, if I remember right)
I just click on the "thread has unread posts" icon, which looks like a peach colored page, and it sends my browser to the first post that I haven't read yet. In any case, if you want the phpBB 2 behavior, click "View new posts" instead of "View unread posts".