Index: /trunk/src/VBox/Additions/common/VBoxGuest/VBoxGuest-win.cpp
===================================================================
--- /trunk/src/VBox/Additions/common/VBoxGuest/VBoxGuest-win.cpp	(revision 41646)
+++ /trunk/src/VBox/Additions/common/VBoxGuest/VBoxGuest-win.cpp	(revision 41647)
@@ -855,10 +855,10 @@
             }
 
+            VBoxGuestMouseSetNotifyCallback *pInfo = (VBoxGuestMouseSetNotifyCallback*)pvBuf;
+
+            /* we need a lock here to avoid concurrency with the set event functionality */
             KIRQL OldIrql;
-            VBoxGuestMouseSetNotifyCallback *pInfo = (VBoxGuestMouseSetNotifyCallback*)pvBuf;
-            /* we need a lock here to avoid concurrency with the set event functionality */
             KeAcquireSpinLock(&pDevExt->win.s.MouseEventAccessLock, &OldIrql);
-            pDevExt->win.s.pfnMouseNotify =  pInfo->pfnNotify;
-            pDevExt->win.s.pvMouseNotify =  pInfo->pvNotify;
+            pDevExt->MouseNotifyCallback = *pInfo;
             KeReleaseSpinLock(&pDevExt->win.s.MouseEventAccessLock, OldIrql);