diff --git a/src/mac/carbon/toplevel.cpp b/src/mac/carbon/toplevel.cpp
index bdd38645a1..27d297fac2 100644
--- a/src/mac/carbon/toplevel.cpp
+++ b/src/mac/carbon/toplevel.cpp
@@ -358,12 +358,14 @@ void SetupMouseEvent( wxMouseEvent &wxevent , wxMacCarbonEvent &cEvent )
         {
             wxevent.SetEventType( wxEVT_MOUSEWHEEL ) ;
 
-            // EventMouseWheelAxis axis = cEvent.GetParameter<EventMouseWheelAxis>(kEventParamMouseWheelAxis, typeMouseWheelAxis) ;
+            EventMouseWheelAxis axis = cEvent.GetParameter<EventMouseWheelAxis>(kEventParamMouseWheelAxis, typeMouseWheelAxis) ;
             SInt32 delta = cEvent.GetParameter<SInt32>(kEventParamMouseWheelDelta, typeSInt32) ;
 
             wxevent.m_wheelRotation = delta;
             wxevent.m_wheelDelta = 1;
             wxevent.m_linesPerAction = 1;
+            if ( axis == kEventMouseWheelAxisX )
+                wxevent.m_wheelAxis = 1;
         }
         break ;