list.set_view_all();
list.signal_item_selected.connect(sigc::mem_fun(this, &Dropdown::list_item_selected));
list.signal_autosize_changed.connect(sigc::mem_fun(this, &Dropdown::list_autosize_changed));
list.set_view_all();
list.signal_item_selected.connect(sigc::mem_fun(this, &Dropdown::list_item_selected));
list.signal_autosize_changed.connect(sigc::mem_fun(this, &Dropdown::list_autosize_changed));