diff --git a/reactos/win32ss/include/ntuser.h b/reactos/win32ss/include/ntuser.h
index c123cc79b6b..c345006020e 100644
--- a/reactos/win32ss/include/ntuser.h
+++ b/reactos/win32ss/include/ntuser.h
@@ -3310,6 +3310,7 @@ typedef struct tagKMDDELPARAM
 #define TWOPARAM_ROUTINE_SETMENUBARHEIGHT   0xfffd0050
 #define TWOPARAM_ROUTINE_EXITREACTOS        0xfffd0051
 #define TWOPARAM_ROUTINE_SETGUITHRDHANDLE   0xfffd0052
+#define HWNDLOCK_ROUTINE_SETFOREGROUNDWINDOWMOUSE 0xfffd0053
   #define MSQ_STATE_CAPTURE	0x1
   #define MSQ_STATE_ACTIVE	0x2
   #define MSQ_STATE_FOCUS	0x3