diff --git a/gtk/gtkbin.c b/gtk/gtkbin.c
index 95d814e6e5..388ad7a68e 100644
--- a/gtk/gtkbin.c
+++ b/gtk/gtkbin.c
@@ -43,6 +43,11 @@
 #include "gtkintl.h"
 
 
+struct _GtkBinPriv
+{
+  GtkWidget *child;
+};
+
 static void gtk_bin_add         (GtkContainer   *container,
 			         GtkWidget      *widget);
 static void gtk_bin_remove      (GtkContainer   *container,
@@ -82,21 +87,32 @@ gtk_bin_class_init (GtkBinClass *class)
   container_class->remove = gtk_bin_remove;
   container_class->forall = gtk_bin_forall;
   container_class->child_type = gtk_bin_child_type;
+
+  g_type_class_add_private (class, sizeof (GtkBinPriv));
 }
 
 static void
 gtk_bin_init (GtkBin *bin)
 {
+  GtkBinPriv *priv;
+
+  bin->priv = G_TYPE_INSTANCE_GET_PRIVATE (bin,
+                                           GTK_TYPE_BIN,
+                                           GtkBinPriv);
+  priv = bin->priv;
+
   gtk_widget_set_has_window (GTK_WIDGET (bin), FALSE);
 
-  bin->child = NULL;
+  priv->child = NULL;
 }
 
 
 static GType
 gtk_bin_child_type (GtkContainer *container)
 {
-  if (!GTK_BIN (container)->child)
+  GtkBinPriv *priv = GTK_BIN (container)->priv;
+
+  if (!priv->child)
     return GTK_TYPE_WIDGET;
   else
     return G_TYPE_NONE;
@@ -107,8 +123,9 @@ gtk_bin_add (GtkContainer *container,
 	     GtkWidget    *child)
 {
   GtkBin *bin = GTK_BIN (container);
+  GtkBinPriv *priv = bin->priv;
 
-  if (bin->child != NULL)
+  if (priv->child != NULL)
     {
       g_warning ("Attempting to add a widget with type %s to a %s, "
                  "but as a GtkBin subclass a %s can only contain one widget at a time; "
@@ -116,12 +133,12 @@ gtk_bin_add (GtkContainer *container,
                  g_type_name (G_OBJECT_TYPE (child)),
                  g_type_name (G_OBJECT_TYPE (bin)),
                  g_type_name (G_OBJECT_TYPE (bin)),
-                 g_type_name (G_OBJECT_TYPE (bin->child)));
+                 g_type_name (G_OBJECT_TYPE (priv->child)));
       return;
     }
 
   gtk_widget_set_parent (child, GTK_WIDGET (bin));
-  bin->child = child;
+  priv->child = child;
 }
 
 static void
@@ -129,14 +146,15 @@ gtk_bin_remove (GtkContainer *container,
 		GtkWidget    *child)
 {
   GtkBin *bin = GTK_BIN (container);
+  GtkBinPriv *priv = bin->priv;
   gboolean widget_was_visible;
 
-  g_return_if_fail (bin->child == child);
+  g_return_if_fail (priv->child == child);
 
   widget_was_visible = gtk_widget_get_visible (child);
   
   gtk_widget_unparent (child);
-  bin->child = NULL;
+  priv->child = NULL;
   
   /* queue resize regardless of gtk_widget_get_visible (container),
    * since that's what is needed by toplevels, which derive from GtkBin.
@@ -152,9 +170,10 @@ gtk_bin_forall (GtkContainer *container,
 		gpointer      callback_data)
 {
   GtkBin *bin = GTK_BIN (container);
+  GtkBinPriv *priv = bin->priv;
 
-  if (bin->child)
-    (* callback) (bin->child, callback_data);
+  if (priv->child)
+    (* callback) (priv->child, callback_data);
 }
 
 
@@ -181,9 +200,10 @@ static GtkSizeRequestMode
 gtk_bin_get_request_mode (GtkSizeRequest      *widget)
 {
   GtkBin *bin = GTK_BIN (widget);
+  GtkBinPriv *priv = bin->priv;
 
-  if (bin->child)
-    return gtk_size_request_get_request_mode (GTK_SIZE_REQUEST (bin->child));
+  if (priv->child)
+    return gtk_size_request_get_request_mode (GTK_SIZE_REQUEST (priv->child));
 
   return GTK_SIZE_REQUEST_HEIGHT_FOR_WIDTH;
 }
@@ -193,13 +213,14 @@ get_child_padding_delta (GtkBin         *bin,
 			 gint           *delta_h,
 			 gint           *delta_v)
 {
+  GtkBinPriv *priv = bin->priv;
   gint hmin, vmin, child_hmin, child_vmin;
 
   gtk_size_request_get_width (GTK_SIZE_REQUEST (bin), &hmin, NULL);
   gtk_size_request_get_height (GTK_SIZE_REQUEST (bin), &vmin, NULL);
 
-  gtk_size_request_get_width (GTK_SIZE_REQUEST (bin->child), &child_hmin, NULL);
-  gtk_size_request_get_height (GTK_SIZE_REQUEST (bin->child), &child_vmin, NULL);
+  gtk_size_request_get_width (GTK_SIZE_REQUEST (priv->child), &child_hmin, NULL);
+  gtk_size_request_get_height (GTK_SIZE_REQUEST (priv->child), &child_vmin, NULL);
 
   *delta_h = hmin - child_hmin;
   *delta_v = vmin - child_vmin;
@@ -212,16 +233,17 @@ gtk_bin_get_width_for_height (GtkSizeRequest      *widget,
 			      gint                *natural_width)
 {
   GtkBin *bin = GTK_BIN (widget);
+  GtkBinPriv *priv = bin->priv;
   gint    hdelta, vdelta, child_min, child_nat;
 
-  if (bin->child)
+  if (priv->child)
     {
       get_child_padding_delta (bin, &hdelta, &vdelta);
-      
-      gtk_size_request_get_width_for_height (GTK_SIZE_REQUEST (bin->child),
-						height - vdelta,
-						&child_min, &child_nat);
-      
+
+      gtk_size_request_get_width_for_height (GTK_SIZE_REQUEST (priv->child),
+                                             height - vdelta,
+                                             &child_min, &child_nat);
+
       if (minimum_width)
 	*minimum_width = child_min + hdelta;
       
@@ -239,16 +261,17 @@ gtk_bin_get_height_for_width  (GtkSizeRequest      *widget,
 			       gint                *natural_height)
 {
   GtkBin *bin = GTK_BIN (widget);
+  GtkBinPriv *priv = bin->priv;
   gint    hdelta, vdelta, child_min, child_nat;
 
-  if (bin->child)
+  if (priv->child)
     {
       get_child_padding_delta (bin, &hdelta, &vdelta);
-      
-      gtk_size_request_get_height_for_width (GTK_SIZE_REQUEST (bin->child),
-						width - hdelta,
-						&child_min, &child_nat);
-      
+
+      gtk_size_request_get_height_for_width (GTK_SIZE_REQUEST (priv->child),
+                                             width - hdelta,
+                                             &child_min, &child_nat);
+
       if (minimum_height)
 	*minimum_height = child_min + vdelta;
       
@@ -275,7 +298,7 @@ gtk_bin_get_child (GtkBin *bin)
 {
   g_return_val_if_fail (GTK_IS_BIN (bin), NULL);
 
-  return bin->child;
+  return bin->priv->child;
 }
 
 void
diff --git a/gtk/gtkbin.h b/gtk/gtkbin.h
index 9a3a460d5e..80b6846f2d 100644
--- a/gtk/gtkbin.h
+++ b/gtk/gtkbin.h
@@ -46,13 +46,15 @@ G_BEGIN_DECLS
 
 
 typedef struct _GtkBin       GtkBin;
+typedef struct _GtkBinPriv   GtkBinPriv;
 typedef struct _GtkBinClass  GtkBinClass;
 
 struct _GtkBin
 {
   GtkContainer container;
 
-  GtkWidget *GSEAL (child);
+  /*< private >*/
+  GtkBinPriv *priv;
 };
 
 struct _GtkBinClass