diff --git a/gtk/gtkwindow.c b/gtk/gtkwindow.c
index d9490004e6..398f1ecb4d 100644
--- a/gtk/gtkwindow.c
+++ b/gtk/gtkwindow.c
@@ -1796,8 +1796,13 @@ gtk_window_set_title_internal (GtkWindow   *window,
   if (gtk_widget_get_realized (widget))
     gdk_window_set_title (gtk_widget_get_window (widget), new_title);
 
-  if (priv->titlebar != NULL && update_titlebar)
-    gtk_header_bar_set_title (GTK_HEADER_BAR (priv->titlebar), new_title);
+  if (update_titlebar)
+    {
+      if (GTK_IS_HEADER_BAR (priv->titlebar))
+        gtk_header_bar_set_title (GTK_HEADER_BAR (priv->titlebar), new_title);
+      else if (GTK_IS_HEADER_BAR (priv->title_box))
+        gtk_header_bar_set_title (GTK_HEADER_BAR (priv->title_box), new_title);
+    }
 
   g_object_notify (G_OBJECT (window), "title");
 }