tx.js

function drawOverlay() {

  _divOvr = document.getElementById("divOvr");

  var sParams = "";

  // create the options based on the drop down items
  for (let param of _currentField.parameters) {
      if (param.startsWith("w:listEntry")) {
          var arrStr = param.split(/["]/);
          sParams += "<option>" + arrStr[1] + "</option>";
      }
  }

  // create a new html select object
  if (!_divOvr) {
      _divOvr = document.createElement("select");
      _divOvr.className = "overlay";
      _divOvr.id = "divOvr";
      _divOvr.innerHTML = sParams;
      _container.appendChild(_divOvr);
  }

  // retrieve the field location in the document
  var fldPos = _currentField.bounds.location;

  // and calculate the offset location and zoom factor
  var x = _textView.offsetLeft + (fldPos.x - _txtViewLoc.x) * _zoom;
  var y = _textView.offsetTop + (fldPos.y - _txtViewLoc.y) * _zoom;

  // set position and size
  _divOvr.style.fontSize = (8 * _zoom) + "pt";
  _divOvr.style.zIndex = _textView.style.zIndex + 10;
  _divOvr.style.left = x + "px";
  _divOvr.style.width = (_currentField.bounds.size.width * _zoom) + "px";
  _divOvr.style.minHeight = (_currentField.bounds.size.height * _zoom) + "px";
  _divOvr.style.top = y + "px";

  // add change event to change text of the field
  // when an option has been selected
  $('#divOvr').change(function () {
      var val = $("#divOvr option:selected").val();
      _currentField.text = val;
      removeElement();
  });

  $('#divOvr').focus(function () {
      this.selectedIndex = -1;
      this.focus();
  });

  _divOvr.focus();
}