GtkWidget *button;
button = gtk_button_new();		// REF count = 1

g_object_ref(G_OBJECT( obj ) );		// increment reference count

g_object_unref( G_OBJECT( store ) );	// decrement reference count

* Each ui::gtk3::xxx_impl object calls g_object_ref_sink in the constructor
* Each ui::gtk3::xxx_impl object calls g_object_unref in the destructor
