anchor.diff:        event.preventDefault();
         if (isValidFilename(newFilename))  {
           ok.button('enable');
  -        if (event.keyCode == $.ui.keyCode.ENTER) {
  +        if (event.keyCode === $.ui.keyCode.ENTER) {
             okClicked(newFilename);
             ok.closest('.ui-dialog').remove();
           }
  
positive.code:   fileDelete.click(() => {
      const initialFilename = cd.currentFilename();
      const okInitiallyDisabled = false;
      const okClicked = (filename) => {
        cd.deleteFile(filename);
        cd.loadFile('stdout');
      };
  
negative.code:   // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  
    fileNew.click(() => {
      const initialFilename = `filename${cd.extensionFilenames()[0]}`;
      const okInitiallyDisabled = !isValidFilename(initialFilename);
      const okClicked = filename => {
        cd.newFile(filename, '');
        cd.loadFile(filename);
      };
  