anchor.diff:  
     // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   
  -  var renameFileFromTo = function(oldFilename, newFilename) {
  +  const renameFileFromTo = function(oldFilename, newFilename) {
       cd.saveCodeFromIndividualSyntaxHighlightEditor(oldFilename);
  -    var oldFile = cd.fileContentFor(oldFilename);
  -    var content = oldFile.val();
  -    var scrollTop = oldFile.scrollTop();
  -    var scrollLeft = oldFile.scrollLeft();
  -    var caretPos = oldFile.caret();
  +    const oldFile = cd.fileContentFor(oldFilename);
  +    const content = oldFile.val();
  +    const scrollTop = oldFile.scrollTop();
  +    const scrollLeft = oldFile.scrollLeft();
  +    const caretPos = oldFile.caret();
   
       cd.fileDiv(oldFilename).remove();
   
  
positive.code:       buttons: [ ok, cancel ]
      });
    	input.keyup(function(event) {
        var ok = $('#file-ok');
        var newFilename = $.trim(input.val());
        event.preventDefault();
        if (isValidFilename(newFilename))  {
          ok.button('enable');
  
negative.code: 
  $(function() {
  
    const openDialog = function(name, initialFilename, okInitiallyDisabled, okClicked) {
      const input = makeInput(name, initialFilename);
      const ok = {
        text: 'ok',
        id: 'file-ok',
        disabled: okInitiallyDisabled,
        click: function() {
          const newFilename = $.trim(input.val());
          okClicked(newFilename);
          $(this).remove();
        }
      };
      const cancel = {
        text: 'cancel',
        click: function() { $(this).remove(); }
      };
      const div = $('<div>');
      div.append(input);
      const fileOperationDialog = div.dialog({
        closeOnEscape: true,
        close: function() { $(this).remove(); },
    	  title: cd.dialogTitle(name + '&nbsp;file'),
  