diff --git a/examples/bayes_net_gui_ex.cpp b/examples/bayes_net_gui_ex.cpp
index b92d8d998..ac214e4db 100644
--- a/examples/bayes_net_gui_ex.cpp
+++ b/examples/bayes_net_gui_ex.cpp
@@ -959,7 +959,7 @@ on_evidence_toggled (
 
 // This event is called when the user causes no node to be selected 
 void main_window::
-on_node_deselected ( unsigned long n )
+on_node_deselected ( unsigned long  )
 {
     no_node_selected();
 }