code: function get_full_width_elements()
  {
  	// `Array.from` requires ES6 polyfill.
  	// const full_width_elements = Array.from(document.querySelectorAll('.rrui__fixed-full-width'))
  	const full_width_elements = [].slice.call(document.querySelectorAll('.rrui__fixed-full-width'))
  	full_width_elements.push(document.body)
  	return full_width_elements
  }
docs: "full-width" elements include `document.body` and all `position: fixed` elements which should be marked with this special CSS class.  Make sure to add `.rrui__fixed-full-width` CSS class to all full-width `position: fixed` elements. Such elements must not be `width: 100%` but rather `width: auto` or `left: 0; right: 0;`.