diff --git a/gtk/gtkcombobox.h b/gtk/gtkcombobox.h
index 978e46846d..8a306b66fa 100644
--- a/gtk/gtkcombobox.h
+++ b/gtk/gtkcombobox.h
@@ -63,10 +63,7 @@ struct _GtkComboBoxClass
 
   /*< private >*/
 
-  /* Padding for future expansion */
-  void (*_gtk_reserved1) (void);
-  void (*_gtk_reserved2) (void);
-  void (*_gtk_reserved3) (void);
+  gpointer padding[8];
 };