Firefox wont focus URL bar on startup with custom new tab

When i use my own new tab extension in Firefox it won’t focus the URL bar on startup. My extension overrides both the new tab and the homepage/startup-page. Is there something I can do about that or is that something that has to be added in the browser itself in the future?

My extension only points to a html file which displays some links. There is no code that focuses anything on my page.

This works fine on Chrome/Brave etc…
Does anyone know if there is a way to focus the address bar myself or if a fix is on the way?