Hi @Cedriclorenz,
Thank you for sharing the credentials. I’ve taken a look at your site in Safari and Chrome. I’ve tried a dozen or so URLs but couldn’t find the issue in your screenshot where it is stuck in the wrong place. Could you link us directly to a page where you are seeing this? Also, what version of Safari are you using.
I did notice that in any browser if I resize to a certain width just after the sidebar becomes visible that you see the header logo pop above the nav items. This is because the combined width of the logo + menu items is too large. When the header runs out of space, the natural behavior is to start stacking so you none of the header elements are hidden. It shouldn’t happen if you had a smaller logo or removed one of the nav items. There are also ways with media queries and custom CSS to make small adjustments only on that width of the screen, but that’s a bit more involved.