Quoted from Martijn:Ok, we implemented this behaviour. You can now hide idle topics (that's topics without any updates since you last opened the topic). This toggle has been added to every topic and post activity view and will 'remember' the way it has been set.
We think it's a neat, small addition to the "forum quality update", thanks everybody for coming up with good ideas.
I realize others have mentioned it but I also cannot turn it off no matter what I try. I don't seem to have any way to access my favourite threads now at all unless someone has posted in one.