--- src/osx_cocoa/propgrid_wrap.cpp.orig	2009-09-21 10:44:51.000000000 +0200
+++ src/osx_cocoa/propgrid_wrap.cpp	2009-09-21 10:46:14.000000000 +0200
@@ -3541,7 +3541,7 @@
     }
     else if ( input == Py_None )
     {
-        *v = new wxPGPropArgCls(NULL);
+        *v = new wxPGPropArgCls((const wxPGProperty*) NULL);
     }
     else
     {