g_signal_connect(tree_view, "row-activated", G_CALLBACK(row_activated_cb), model);
selection = gtk_tree_view_get_selection(GTK_TREE_VIEW(tree_view));
g_signal_connect(tree_view, "row-activated", G_CALLBACK(row_activated_cb), model);
selection = gtk_tree_view_get_selection(GTK_TREE_VIEW(tree_view));