diff --git a/gtk/gtkbox.c b/gtk/gtkbox.c
index 9786b3b..0bdd9b5 100644
--- a/gtk/gtkbox.c
+++ b/gtk/gtkbox.c
@@ -118,6 +118,7 @@ struct _GtkBoxPrivate
   gint16          spacing;
 
   guint           default_expand : 1;
+  guint           default_fill   : 1;
   guint           homogeneous    : 1;
   guint           spacing_set    : 1;
 };
@@ -329,6 +330,7 @@ gtk_box_init (GtkBox *box)
   private->children = NULL;
 
   private->default_expand = FALSE;
+  private->default_fill = FALSE;
   private->homogeneous = FALSE;
   private->spacing = 0;
   private->spacing_set = FALSE;
@@ -1638,6 +1640,7 @@ _gtk_box_set_old_defaults (GtkBox *box)
   private = box->priv;
 
   private->default_expand = TRUE;
+  private->default_fill = TRUE;
 }
 
 static void
@@ -1648,7 +1651,7 @@ gtk_box_add (GtkContainer *container,
 
   gtk_box_pack_start (GTK_BOX (container), widget,
                       priv->default_expand,
-                      priv->default_expand,
+                      priv->default_fill,
                       0);
 }
 
