It's all about where you click.
Screenshot to understand:

http://i34.tinypic.com/fuc289.jpgIf you click on the SA icon, which I made a red square around on the screenshot, you see all recent unread topics.
Meaning its supposed to show only topics that are unread by you.
However, if you click on the section name, in this case SA:MP General (I made a green square around it on the screenshot), it will show you all topics as normal.
So it's pretty much just a function, not sure if it's working perfect.
Hope you understand now
