Glib::RefPtr<Gtk::TreeModelSort> sorted_store(Gtk::TreeModelSort::create(layer_group_tree_store_));
sorted_store->set_default_sort_func(sigc::ptr_fun(&studio::LayerGroupTreeStore::time_sorter));
sorted_store->set_sort_func(model.time.index(),sigc::ptr_fun(&studio::LayerGroupTreeStore::time_sorter));
Glib::RefPtr<Gtk::TreeModelSort> sorted_store(Gtk::TreeModelSort::create(layer_group_tree_store_));
sorted_store->set_default_sort_func(sigc::ptr_fun(&studio::LayerGroupTreeStore::time_sorter));
sorted_store->set_sort_func(model.time.index(),sigc::ptr_fun(&studio::LayerGroupTreeStore::time_sorter));