Gtk.WidgetPath.prototype.append_with_siblings

function append_with_siblings(siblings:Gtk.WidgetPath, sibling_index:Number):Number {
    // Gjs wrapper for gtk_widget_path_append_with_siblings()
}

Appends a widget type with all its siblings to the widget hierarchy represented by path. Using this function instead of Gtk.WidgetPath.prototype.append_type will allow the CSS theming to use sibling matches in selectors and apply :nth-child() pseudo classes. In turn, it requires a lot more care in widget implementations as widgets need to make sure to call Gtk.Widget.prototype.reset_style on all involved widgets when the siblings path changes.

Since 3.2