Yellow arrows next to thread dissappear even though I never read them.

Rob,
When I am on Ferrari Chat and looking at the General Discussion section and open a thread that has a yellow arrow in its prefixs. This means that I haven't read it yet. However if I pick one lets say like 10 down from the top with a yellow arrow, when I come back to the site after like an hour, all the ones below I picked have the yellow arrows taken away like I already read the thread. But I really haven't read it yet. Like on the old board you had them change color from blue to pink after you have read it. Is there away to change this or is it my computer. I know this is not the best explaination, I hope you can understand it, if not let me know. Thanks for all your help man!!

~Mike P.