--- xc/programs/Xserver/dix/events.c.SAV	2005-11-25 17:18:04.000000000 -0700
+++ xc/programs/Xserver/dix/events.c	2005-11-25 17:18:24.000000000 -0700
@@ -3024,7 +3024,7 @@
 #if !defined(XFree86Server) || !defined(XINPUT)
 	    xE->u.u.detail = butc->map[key];
 #endif
-	    if (xE->u.u.detail == 0)
+	    if ((xE->u.u.detail == 0) || (butc->map[key] == 0))
 		return;
 	    if (xE->u.u.detail <= 5)
 		butc->state |= (Button1Mask >> 1) << xE->u.u.detail;
@@ -3043,7 +3043,7 @@
 #if !defined(XFree86Server) || !defined(XINPUT)
 	    xE->u.u.detail = butc->map[key];
 #endif
-	    if (xE->u.u.detail == 0)
+	    if ((xE->u.u.detail == 0) || (butc->map[key] == 0))
 		return;
 	    if (xE->u.u.detail <= 5)
 		butc->state &= ~((Button1Mask >> 1) << xE->u.u.detail);