anchor.diff:  
     filenames.selectNext = () => selectFileInFileList(nextFilename());
     filenames.selectPrevious = () => selectFileInFileList(previousFilename());
  +  filenames.refresh = () => rebuildFilenameList();
   
     const nextFilename = () => filenames.sorted()[indexOfNext()];
     const indexOfNext = () => {
  
positive.code:   cd.currentFilename = () => theCurrentFilename;
  
    //- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    // Load a named file
    //- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  
    cd.unloadFile = (filename) => cd.kata.editor.hideFile(filename);
  
    cd.loadFile = (filename) => {
      // unshow what is currently being shown
      cd.unloadFile('stdout');
      cd.unloadFile('stderr');
      cd.unloadFile('status');
      cd.unloadFile(cd.currentFilename());
  
      cd.kata.editor.showFile(filename);
  
      cd.focusSyntaxHighlightEditor(filename);
      if (!cd.isOutputFile(filename)) {
        selectFileInFileList(filename);
        theCurrentFilename = filename;
      }
      setRenameAndDeleteButtons(filename);
      cd.kata.tabs.setFilename(filename);
    };
  
    const selectFileInFileList = (filename) => {
      // Can't do $('radio_' + filename) because filename
  
negative.code: 
    //- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  
    const rebuildFilenameList = () => {
      const selected = filenames.selected(); // Try to retain
      const sorted = cd.sortedFilenames();
  