Threads with unread messages

[Sarah Vandegoor]

If a thread holds messages that I haven't read yet, then the thread title is shown in bold in the thread list and there is an indication to "Go to the first unread post". There are quite some threads that I haven't even opened. So, these contain unread posts as well. I was wondering how this mechanism works? And how far does it go back? Is there a system setting or option to enable/disable this?
Thanks

 

[Amaury]

They will stay as unread until you view them. How long depends on the read marking data lifetime option. By default, it's 30 days.