diff --git a/win32ss/user/ntuser/painting.c b/win32ss/user/ntuser/painting.c
index a684d74c364..0574c7bf23e 100644
--- a/win32ss/user/ntuser/painting.c
+++ b/win32ss/user/ntuser/painting.c
@@ -285,9 +285,11 @@ IntGetNCUpdateRgn(PWND Window, BOOL Validate)
          return HRGN_WINDOW;
       }
 
-      NcType = IntGdiGetRgnBox(hRgnNonClient, &update);
+      NcType = IntGdiGetRgnBox(Window->hrgnUpdate, &update);
 
       RgnType = NtGdiCombineRgn(hRgnNonClient, hRgnNonClient, hRgnWindow, RGN_DIFF);
+      if ((RgnType != ERROR) && (RgnType != NULLREGION))
+         RgnType = NtGdiCombineRgn(hRgnNonClient, hRgnNonClient, Window->hrgnUpdate, RGN_AND);
 
       if (RgnType == ERROR)
       {