private Optional<ItemWithSeparatorAbove> findFrameWithSeparator() {
      // We check only the first frame; otherwise, it's not clear what to do.
      // Might be reconsidered in the future.
      return hiddenFrames.get(0) instanceof ItemWithSeparatorAbove frame
             ? Optional.of(frame)
             : Optional.empty();
    }
private Optional<ItemWithSeparatorAbove> findFrameWithSeparator()