Thanks for finding the problem.
I’m also a bit sad that I can’t use that theme.:'( Looked good anyway. A bit shady footer with weird links but I was planning to remove them anyway. But I don’t have the time to find a replacement for that TimTumb issue. So I decided to go for another theme.
But the best thing was: It wasn’t a flaw of my settings and it wasn’t some quirky thing from WordPress. 😀
Thanks Jorge & Ipstenu