diff --git a/src/kits/interface/Window.cpp b/src/kits/interface/Window.cpp
index 15930131d4..043b082d94 100644
--- a/src/kits/interface/Window.cpp
+++ b/src/kits/interface/Window.cpp
@@ -50,6 +50,7 @@
 
 // Local Includes --------------------------------------------------------------
 #include "WindowAux.h"
+#include "MessageUtils.h"
 
 // Local Defines ---------------------------------------------------------------