code: function removeGutters(editor) {
          Editor.unregisterGutter(GUTTER_NAME);
          $(editor.getRootElement()).removeClass("folding-enabled");
          CodeMirror.defineOption("foldGutter", false, null);
      }
docs: Remove the fold gutter for a given CodeMirror instance.
  @param {Editor} editor the editor instance whose gutter should be removed