anchor.diff:      });
     };
   
  -  const tr = function(key, what) {
  +  const tr = (key, what) => {
       return '<tr>' +
         '<td style="text-align:right;">' + key + '</td>' +
         '<td>==</td>' +
  
positive.code: 
    const hotkeysButton = $('#hotkeys-button');
  
    const hotkeysDialog = function() {
      var html = '';
      html += '<div id="hotkeys-dialog">';
      html += '<table>';
      html += tr('Alt-T', 'runs the tests');
      html += tr('Alt-O', 'moves to/from the output file');
      html += tr('Alt-J', 'cycles forwards through the source files');
      html += tr('Alt-K', 'cycles bakwards through the source files');
      html += '</table>';
      html += '<hr/>';
      html += '<table>';
  
negative.code:       closeOnEscape: true,
                modal: true,
                title: cd.dialogTitle('hotkeys'),
              buttons: { close: () => {
                  node.remove();
                  cd.editorRefocus();
                }
              },
          beforeClose: (event) => {
            if (event.keyCode === $.ui.keyCode.ESCAPE) {
              node.remove();
              cd.editorRefocus();
              return true;
            }
  