diff --git a/hw/xwin/winmultiwindowshape.c b/hw/xwin/winmultiwindowshape.c
index 44007027a..353235760 100644
--- a/hw/xwin/winmultiwindowshape.c
+++ b/hw/xwin/winmultiwindowshape.c
@@ -71,6 +71,9 @@ winUpdateRgnMultiWindow (WindowPtr pWin)
 {
   SetWindowRgn (winGetWindowPriv(pWin)->hWnd,
 		winGetWindowPriv(pWin)->hRgn, TRUE);
+
+  /* The system now owns the region specified by the region handle and will delete it when it is no longer needed. */
+  winGetWindowPriv(pWin)->hRgn = NULL;
 }