anchor.diff:    };
   
     tabs.toggle = () => {
  -    // Alt-O tabs hot-key navigation
  +    // Alt-O tabs hot-key navigation (skip [status] and [REPL])
       // See app/assets/javascripts/cyber-dojo_codemirror.js
       // See app/views/shared/_hotkeys.html.erb
       switch (tabs.selected().text()) {
  
positive.code:     const tabNames = [];
      tabNames.push(tabs.stdout().text());
      tabNames.push(tabs.stderr().text());
      tabNames.push('status');
      tabNames.push(tabs.repl().text());
      return tabNames.includes(filename);
  
negative.code:   setupFileTabClickHandler(tabs.filename());
    setupFileTabClickHandler(tabs.stdout());
    setupFileTabClickHandler(tabs.stderr());
    setupFileTabClickHandler(tabs.status());
    setupReplTabClickHandler(tabs.repl());
  
  });
  