diff --git a/gtk/gtktreeview.h b/gtk/gtktreeview.h
index e34856a13b..f98b2343be 100644
--- a/gtk/gtktreeview.h
+++ b/gtk/gtktreeview.h
@@ -64,7 +64,7 @@ struct _GtkTreeView
 {
   GtkContainer parent;
 
-  GtkTreeViewPrivate *priv;
+  GtkTreeViewPrivate *GSEAL (priv);
 };
 
 struct _GtkTreeViewClass