diff --git a/PowerEditor/src/Notepad_plus.h b/PowerEditor/src/Notepad_plus.h
index d209080fd..b9b3da927 100644
--- a/PowerEditor/src/Notepad_plus.h
+++ b/PowerEditor/src/Notepad_plus.h
@@ -126,6 +126,7 @@
 
 #include "localization.h"
 #include <vector>
+#include <iso646.h>
 
 
 #define MENU 0x01