diff --git a/MagickCore/xwindow.c b/MagickCore/xwindow.c
index 262f521..4304c16 100644
--- a/MagickCore/xwindow.c
+++ b/MagickCore/xwindow.c
@@ -76,6 +76,7 @@
 #include "MagickCore/string-private.h"
 #include "MagickCore/transform.h"
 #include "MagickCore/utility.h"
+#include "MagickCore/utility-private.h"
 #include "MagickCore/widget.h"
 #include "MagickCore/widget-private.h"
 #include "MagickCore/xwindow.h"