@Override
    public void rememberShownAnnotations(@NotNull T viewer) {
      boolean[] annotationsShown = new boolean[2];
      annotationsShown[0] = isAnnotationShown(viewer, Side.LEFT);
      annotationsShown[1] = isAnnotationShown(viewer, Side.RIGHT);

      viewer.getRequest().putUserData(Holder.ANNOTATIONS_SHOWN_KEY, annotationsShown);
    }
@Override
    public void rememberShownAnnotations(@NotNull T viewer)