--- a/ui/ui/ui.h	Tue Jan 24 18:46:47 2017 +0100
+++ b/ui/ui/ui.h	Fri Nov 10 17:17:14 2017 +0100
@@ -1,7 +1,7 @@
 /*
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
  *
- * Copyright 2014 Olaf Wintermann. All rights reserved.
+ * Copyright 2017 Olaf Wintermann. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -30,6 +30,7 @@
 #define	UI_H
 
 #include "toolkit.h"
+#include "container.h"
 #include "menu.h"
 #include "toolbar.h"
 #include "window.h"