fn build_display_pane(title: &str, capture_path: &str) -> DisplayPaneWidgets {
    let root = gtk::Box::new(gtk::Orientation::Vertical, 10);
    root.add_css_class("display-card");
    root.set_hexpand(true);
    root.set_vexpand(true);

    let header = gtk::Box::new(gtk::Orientation::Horizontal, 8);
    header.set_hexpand(true);
    let title_label = gtk::Label::new(Some(title));
    title_label.add_css_class("title-4");
    title_label.set_halign(gtk::Align::Start);
    title_label.set_hexpand(true);
    let capture_label = gtk::Label::new(Some(capture_path));
    capture_label.add_css_class("dim-label");
    capture_label.set_halign(gtk::Align::End);
    capture_label.set_ellipsize(pango::EllipsizeMode::Start);
    header.append(&title_label);
    header.append(&capture_label);
    root.append(&header);

    let picture = gtk::Picture::new();
    picture.set_hexpand(true);
    picture.set_vexpand(true);
    picture.set_halign(gtk::Align::Fill);
    picture.set_valign(gtk::Align::Fill);
    picture.set_can_shrink(true);
    picture.set_keep_aspect_ratio(true);
    picture.set_size_request(EYE_PREVIEW_MIN_WIDTH, EYE_PREVIEW_MIN_HEIGHT);

    let preview_box = gtk::Box::new(gtk::Orientation::Vertical, 0);
    preview_box.set_hexpand(true);
    preview_box.set_vexpand(true);
    preview_box.set_halign(gtk::Align::Fill);
    preview_box.set_valign(gtk::Align::Fill);
    preview_box.set_size_request(EYE_PREVIEW_MIN_WIDTH, EYE_PREVIEW_MIN_HEIGHT);
    let preview_frame = gtk::AspectFrame::new(0.5, 0.5, 16.0 / 9.0, false);
    preview_frame.set_hexpand(false);
    preview_frame.set_vexpand(false);
    preview_frame.set_halign(gtk::Align::Center);
    preview_frame.set_valign(gtk::Align::Center);
    preview_frame.set_size_request(EYE_PREVIEW_MIN_WIDTH, EYE_PREVIEW_MIN_HEIGHT);
    preview_frame.set_child(Some(&picture));
    preview_box.append(&preview_frame);

    let placeholder = gtk::Label::new(Some(
        "This feed is running in its own window.\nUse Return To Preview to dock it back here.",
    ));
    placeholder.set_wrap(true);
    placeholder.set_justify(gtk::Justification::Center);
    placeholder.set_halign(gtk::Align::Center);
    placeholder.set_valign(gtk::Align::Center);

    let placeholder_box = gtk::Box::new(gtk::Orientation::Vertical, 6);
    placeholder_box.add_css_class("display-placeholder");
    placeholder_box.set_hexpand(true);
    placeholder_box.set_vexpand(true);
    placeholder_box.set_size_request(EYE_PREVIEW_MIN_WIDTH, EYE_PREVIEW_MIN_HEIGHT);
    placeholder_box.append(&placeholder);

    let stack = gtk::Stack::new();
    stack.set_hexpand(true);
    stack.set_vexpand(true);
    stack.add_named(&preview_box, Some("preview"));
    stack.add_named(&placeholder_box, Some("placeholder"));
    stack.set_visible_child_name("preview");
    root.append(&stack);

    let feed_source_combo = gtk::ComboBoxText::new();
    feed_source_combo.add_css_class("compact-combo");
    feed_source_combo.set_tooltip_text(Some("Eye source for this pane."));
    feed_source_combo.set_hexpand(true);
    feed_source_combo.set_size_request(0, -1);
    let capture_resolution_combo = gtk::ComboBoxText::new();
    capture_resolution_combo.add_css_class("compact-combo");
    capture_resolution_combo.set_tooltip_text(Some("Eye capture mode."));
    capture_resolution_combo.set_size_request(0, -1);
    capture_resolution_combo.set_hexpand(true);
    let breakout_combo = gtk::ComboBoxText::new();
    breakout_combo.add_css_class("compact-combo");
    breakout_combo.set_tooltip_text(Some("Breakout window size."));
    breakout_combo.set_size_request(0, -1);
    breakout_combo.set_hexpand(true);
    let action_button = gtk::Button::with_label("Break Out");
    stabilize_button(&action_button, 104);
    action_button.set_halign(gtk::Align::End);
    let stream_status = gtk::Label::new(Some("Preview pending"));
    stream_status.add_css_class("status-line");
    stream_status.add_css_class("eye-inline-status");
    stream_status.set_halign(gtk::Align::Fill);
    stream_status.set_valign(gtk::Align::Center);
    stream_status.set_hexpand(true);
    stream_status.set_ellipsize(pango::EllipsizeMode::End);
    stream_status.set_single_line_mode(true);
    stream_status.set_width_chars(12);
    stream_status.set_max_width_chars(18);
    stream_status.set_tooltip_text(Some("Eye stream status."));
    let footer_shell = gtk::Box::new(gtk::Orientation::Vertical, 6);
    let controls_grid = gtk::Grid::new();
    controls_grid.set_column_spacing(8);
    controls_grid.set_row_spacing(8);
    controls_grid.set_hexpand(true);
    let feed_row = build_inline_combo_row("Feed", &feed_source_combo, 7);
    let capture_row = build_inline_combo_row("Capture", &capture_resolution_combo, 7);
    let breakout_row = build_inline_combo_row("Display", &breakout_combo, 7);
    feed_row.set_hexpand(true);
    capture_row.set_hexpand(true);
    breakout_row.set_hexpand(true);
    controls_grid.attach(&feed_row, 0, 0, 1, 1);
    controls_grid.attach(&capture_row, 1, 0, 2, 1);
    controls_grid.attach(&breakout_row, 0, 1, 1, 1);
    controls_grid.attach(&stream_status, 1, 1, 1, 1);
    controls_grid.attach(&action_button, 2, 1, 1, 1);
    footer_shell.append(&controls_grid);
    root.append(&footer_shell);

    DisplayPaneWidgets {
        root,
        stack,
        preview_frame,
        picture,
        stream_status,
        placeholder,
        feed_source_combo,
        capture_resolution_combo,
        breakout_combo,
        action_button,
        preview_binding: Rc::new(RefCell::new(None)),
        title: title.to_string(),
    }
}