Hi @easydeutsch ,
I wanted to follow up with an update. We were able to identify the cause of the issue, and it was coming from the custom code you wrote inside the HTML section of your home page.
The root of the problem was that the custom script on that page was written broadly. It was scanning every div on the page and force-modifying any element that matched certain Pickaxe-style z-index values or class patterns. Because the Portal side navigation and the top-right menu also use those same kinds of interface layers, the script was unintentionally targeting real Pickaxe navigation elements and disabling them. That is why the menus would appear briefly and then disappear once the page finished loading.
We have now adjusted the HTML section on your home page so that it no longer interferes with the Portal navigation. After that change, the menu persists correctly on both desktop and mobile.
We have also saved the original contents of the HTML section. If you would like a copy of the original version, please let us know and we can send it to you by email.