diff --git a/Simulator/GUI/gui.cxx b/Simulator/GUI/gui.cxx
index 5a50fe92d..dc661d141 100644
--- a/Simulator/GUI/gui.cxx
+++ b/Simulator/GUI/gui.cxx
@@ -61,6 +61,7 @@
 
 #include "gui.h"
 
+FG_USING_STD(cout);
 FG_USING_STD(string);
 
 puFont guiFnt = 0;