diff --git a/src/osgProducer/Viewer.cpp b/src/osgProducer/Viewer.cpp
index b036e4b59..3c62e3847 100644
--- a/src/osgProducer/Viewer.cpp
+++ b/src/osgProducer/Viewer.cpp
@@ -25,6 +25,11 @@ using namespace Producer;
 using namespace osgProducer;
 using namespace osg;
 
+
+#ifdef __APPLE__
+#define SINGLE_THREAD_KEYBOARDMOUSE
+#endif
+
 //////////////////////////////////////////////////////////////////////////////
 //
 // Picking intersection visitor.
@@ -604,8 +609,6 @@ public:
     }
 };
 
-//#define SINGLE_THREAD_KEYBOARDMOUSE
-
 bool Viewer::realize()
 {
     if (_realized) return _realized;