anchor.diff:      const $filenames = $('#filename-list');
       const initialFilename = $('.filename.selected', $filenames).text().trim();
       const okInitiallyDisabled = false;
  -    const okClicked = filename => {
  +    const okClicked = (filename) => {
         cd.kata.editor.deleteFile(filename);
         cd.kata.filenames.refresh();
         cd.kata.filenames.select(cd.kata.filenames.top());
  
positive.code: 
    cd.openRenameFileDialog = (originator, filename) => {
      const okInitiallyDisabled = true;
      const okClicked = newFilename => {
        cd.kata.editor.renameFile(filename, newFilename);
        cd.kata.filenames.refresh();
        cd.kata.filenames.select(newFilename);
  
negative.code:   const openNewFileDialog = () => {
      const initialFilename = `filename${cd.extensionFilenames()[0]}`;
      const okInitiallyDisabled = !isValidFilename(initialFilename);
      const okClicked = (newFilename) => {
        cd.kata.editor.createFile(newFilename, {content:''});
        cd.kata.filenames.refresh();
        cd.kata.filenames.select(newFilename);
  