diff --git a/gtk/gtkcellareabox.c b/gtk/gtkcellareabox.c
index 05ec4bb957..c682ec617a 100644
--- a/gtk/gtkcellareabox.c
+++ b/gtk/gtkcellareabox.c
@@ -312,7 +312,7 @@ gtk_cell_area_box_class_init (GtkCellAreaBoxClass *class)
                                                      0,
                                                      G_MAXINT,
                                                      0,
-                                                     GTK_PARAM_READWRITE));
+                                                     GTK_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY));
 
   /* Cell Properties */
   /**