Scrolling the add-ons list will also scroll the header that includes the filter and other stuff

Please decouple the add-ons list header from the actual add-ons list, so that it will stay on top while one can scroll the list of add-ons, while still be able to filter the add-ons or install a new add-on and so on.
List scroll position must not be remembered when switching filters, but it would be nice to have.