IMPLEMENT_DYNAMIC_CLASS(wxSpinButton, wxControl);
IMPLEMENT_DYNAMIC_CLASS(wxSpinEvent, wxNotifyEvent);
-static void CalcSizes( wxPoint pt, wxSize sz,
+static void CalcSizes( const wxPoint& pt, const wxSize& sz,
wxPoint& pt1, wxSize& sz1,
wxPoint& pt2, wxSize& sz2,
bool isVertical )