diff --git a/reactos/subsystems/win32/win32k/ntuser/window.c b/reactos/subsystems/win32/win32k/ntuser/window.c
index 00d454b05bd..7be4ef57280 100644
--- a/reactos/subsystems/win32/win32k/ntuser/window.c
+++ b/reactos/subsystems/win32/win32k/ntuser/window.c
@@ -472,6 +472,7 @@ static LRESULT co_UserFreeWindow(PWND Window,
    if(Window->hrgnClip)
    {
       GreDeleteObject(Window->hrgnClip);
+      Window->hrgnClip = NULL;
    }
 
 //   ASSERT(Window != NULL);