--- ./nx-X11/programs/Xserver/xfixes/select.c.X.original	2015-02-13 14:03:44.792440567 +0100
+++ ./nx-X11/programs/Xserver/xfixes/select.c	2015-02-10 19:13:13.504697118 +0100
@@ -78,7 +78,9 @@
     }
     for (e = selectionEvents; e; e = e->next)
     {
-	if (e->selection == selection->selection && (e->eventMask & eventMask))
+	if (e->selection == selection->selection && 
+	    (e->eventMask & eventMask) &&
+	    !e->pClient->clientGone)
 	{
 	    xXFixesSelectionNotifyEvent	ev;
 
