anchor.diff:          }
         }
       });
  +
     	input.keyup(function(event) {
         const ok = $('#file-ok');
         const newFilename = $.trim(input.val());
  
positive.code: $(() => {
  
    const fileButtons = $('#file-operations');
  
    // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  
    fileButtons.find('#new').click(() => {
      const initialFilename = 'filename' + cd.extensionFilenames()[0];
      const okInitiallyDisabled = !isValidFilename(initialFilename);
      const okClicked = (filename) => {
        cd.newFileContent(filename, '');
      };
      openDialog('new', initialFilename, okInitiallyDisabled, okClicked);
    });
  
    // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  
    fileButtons.find('#rename').click(() => {
      const initialFilename = cd.currentFilename();
      const okInitiallyDisabled = true;
      const okClicked = (filename) => {
        renameFileFromTo(initialFilename, filename);
      };
      openDialog('rename', initialFilename, okInitiallyDisabled, okClicked);
    });
  
    // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  
    fileButtons.find('#delete').click(() => {
      const initialFilename = cd.currentFilename();
      const okInitiallyDisabled = false;
      const okClicked = (filename) => {
        cd.deleteFile(filename);
      };
      openDialog('delete', initialFilename, okInitiallyDisabled, okClicked);
    });
  
    // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  
    const openDialog = function(name, initialFilename, okInitiallyDisabled, okClicked) {
      const input = makeInput(name, initialFilename);
      const ok = {
        text: 'ok',
        id: 'file-ok',
  
negative.code:         cd.editorRefocus();
        }
      };
  
      const div = $('<div>');
      div.append(input);
      const fileOperationDialog = div.dialog({
  