l;
        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.length - 1]);
            const bottom = lastEl.offsetTop + lastEl.offsetHeight;
          