Hi again Michiel,
I think you want that first checkbox selected, although I don’t know the translated string. If it means “Hidden on load” you need to select it. But that won’t solve your loading problem.
Just to double check - You set the dataset to display fewer items than you have in your collection, right?
If that’s not the problem, can you share your site URL with me because from what I can see the code looks ok.
-Jeff