GtkWidget *config = gtk_notebook_new();
g_signal_connect(window, "delete-event", G_CALLBACK(on_delete), NULL);
g_signal_connect(window, "key-press-event", G_CALLBACK(on_key_press), NULL);
+ gtk_widget_set_size_request(GTK_WIDGET(viewer), 300, 300);
gtk_notebook_set_tab_pos(GTK_NOTEBOOK(config), GTK_POS_BOTTOM);
gtk_container_add(GTK_CONTAINER(window), vbox);
gtk_box_pack_start(GTK_BOX(vbox), GTK_WIDGET(viewer), TRUE, TRUE, 0);