diff --git a/src/GEOMGUI/GeometryGUI.cxx b/src/GEOMGUI/GeometryGUI.cxx
index a230d3725..674eb2869 100644
--- a/src/GEOMGUI/GeometryGUI.cxx
+++ b/src/GEOMGUI/GeometryGUI.cxx
@@ -1696,7 +1696,7 @@ void GeometryGUI::createPreferences()
 				     LightApp_Preferences::Selector,
 				     "Geometry", "back_material" );
 
-  int nb = 4;
+  const int nb = 4;
   int wd[nb];
   int iter=0;