CMS Permission preview problem
 

I need some help figuring out what I'm doing wrong.

I have 5 sections. On four of them, permissions are set so that anybody can read. The last one only has read access to a certain usergroup. I still want everybody else to see previews, and from what I'd gathered, I then need to make sure Permission preview is set to yes. So I've done that, but still the previews are missing for articles in the closed section. What am I doing wrong?