- GisCallback *callback = gis_callback_new(expose, self);
- gis_viewer_add(viewer, GIS_OBJECT(callback), GIS_LEVEL_BACKGROUND, 0);
- gis_viewer_add(viewer, GIS_OBJECT(self->background), GIS_LEVEL_BACKGROUND, 0);
+ gpointer ref1, ref2;
+ ref1 = gis_viewer_add(viewer, GIS_OBJECT(callback), GIS_LEVEL_BACKGROUND, FALSE);
+ ref2 = gis_viewer_add(viewer, GIS_OBJECT(background), GIS_LEVEL_BACKGROUND, FALSE);
+ self->refs = g_list_prepend(self->refs, ref1);
+ self->refs = g_list_prepend(self->refs, ref2);