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