diff --git a/clutter/clutter-box.c b/clutter/clutter-box.c
index 6b8253eac..f3c0648ab 100644
--- a/clutter/clutter-box.c
+++ b/clutter/clutter-box.c
@@ -281,7 +281,8 @@ clutter_box_set_property (GObject      *gobject,
   switch (prop_id)
     {
     case PROP_LAYOUT_MANAGER:
-      priv->manager = g_value_dup_object (value);
+      priv->manager = g_value_get_object (value);
+      g_object_ref_sink (priv->manager);
       break;
 
     default:
diff --git a/clutter/clutter-layout-manager.c b/clutter/clutter-layout-manager.c
index f9e59087f..912ccd2d3 100644
--- a/clutter/clutter-layout-manager.c
+++ b/clutter/clutter-layout-manager.c
@@ -23,7 +23,9 @@
                    G_OBJECT_TYPE_NAME (_obj),                           \
                    (method));                           } G_STMT_END
 
-G_DEFINE_ABSTRACT_TYPE (ClutterLayoutManager, clutter_layout_manager, G_TYPE_OBJECT);
+G_DEFINE_ABSTRACT_TYPE (ClutterLayoutManager,
+                        clutter_layout_manager,
+                        G_TYPE_INITIALLY_UNOWNED);
 
 static void
 layout_manager_real_get_preferred_width (ClutterLayoutManager *manager,
diff --git a/clutter/clutter-layout-manager.h b/clutter/clutter-layout-manager.h
index f93e68a02..e053c658e 100644
--- a/clutter/clutter-layout-manager.h
+++ b/clutter/clutter-layout-manager.h
@@ -30,7 +30,7 @@ typedef struct _ClutterLayoutManagerClass       ClutterLayoutManagerClass;
  */
 struct _ClutterLayoutManager
 {
-  GObject parent_instance;
+  GInitiallyUnowned parent_instance;
 };
 
 /**
@@ -43,7 +43,7 @@ struct _ClutterLayoutManager
  */
 struct _ClutterLayoutManagerClass
 {
-  GObjectClass parent_class;
+  GInitiallyUnownedClass parent_class;
 
   void (* get_preferred_width)  (ClutterLayoutManager   *manager,
                                  ClutterContainer       *container,