if show_scrollbar {

                    let content_length = self.items.len();

                    let scroller = Scrollbar::default()

                        .begin_symbol(None)

                        .track_symbol(None)

                        .end_symbol(None)

                        .thumb_symbol("┃")

                        .style(if has_focus {

                            Style::default()

                        } else {

                            Style::default().dim()

                        });

                    let mut state = ScrollbarState::default()

                        .content_length(content_length)

                        .viewport_content_length(1)

                        .position(state.internal.offset());

                    frame.render_stateful_widget(scroller, scroller_area, &mut state);

                }