Use navigation as a header

Hi,

I'm working on updating my headers on two different pages. It's going pretty well with some good guidance.

But on of the pages there is a weird issue where the "Use navigation as header" option is not available.

It's not a big issue as I can simply disable the header element and then only the navigations show.

But I would still like to find out what I'm doing wrong so this option doesn't show.

Screenshot here: https://ln2.sync.com/dl/56cd569d0/kfmzz6wk-2c73qbnp-an46a6ua-qghdsxj3

I've activated all modules but it still doesn't show. What am I missing?

Kind regards
Lars