*** src/gui_mac.c	Sat Aug 19 11:08:34 2006
--- src/gui_mac_patched.c	Sat Aug 19 11:08:27 2006
***************
*** 2480,2485 ****
--- 2480,2493 ----
      UInt32	mod;
      SInt32	delta;
      int_u	vim_mod;
+     EventMouseWheelAxis axis;
+ 
+     if (noErr == GetEventParameter(theEvent, kEventParamMouseWheelAxis,
+                 typeMouseWheelAxis, NULL, sizeof(axis), NULL, &axis))
+     {
+         if (axis != kEventMouseWheelAxisY) //only scroll with vertical movement
+             return noErr;
+     }
  
      if (noErr != GetEventParameter(theEvent, kEventParamMouseWheelDelta,
  			      typeSInt32, NULL, sizeof(SInt32), NULL, &delta))
