stack sidebar: Make final

This should not be subclassed.

1 files changed, 13 insertions, 0 deletions

diff --git a/gtk/gtkstacksidebar.c b/gtk/gtkstacksidebar.c
index 29b39f3d90..3beb195471 100644
--- a/gtk/gtkstacksidebar.c
+++ b/gtk/gtkstacksidebar.c
@@ -55,6 +55,19 @@
  * pages.
  */
 
+typedef struct _GtkStackSidebarPrivate GtkStackSidebarPrivate;
+typedef struct _GtkStackSidebarClass   GtkStackSidebarClass;
+
+struct _GtkStackSidebar
+{
+  GtkBin parent;
+};
+
+struct _GtkStackSidebarClass
+{
+  GtkBinClass parent_class;
+};
+
 struct _GtkStackSidebarPrivate
 {
   GtkListBox *list;