let top = null;
          let height = null;
          let parent = null;
          if (lineIds.length > 0) {
              //compute the position of the single el (top and bottom and make a div)
              const el = window.document.getElementById(lineIds[0]);
              top = el.offsetTop;
              height = el.offsetHeight;
              parent = el.parentElement.parentElement;
            if (lineIds.length > 1) {
              const lastEl = window.document.getElementById(lineIds[lineIds.leng