[Tutor] wxPython dialog problem

[Garry Willgoose]

I'm just porting an old code from a GUI in Tkinter to one in wxPython  
and am having a problem with one of the dialog widgets. This is on  
OSX. The code below gives the result

result= 5104 5103 5104

as expected but if I substitute the single line form that is commented  
out (as per the wxPython book) I get

result= 2 5103 5104

can anyone enlighten me as to what is going on? I;m on OSX python  
2.5.2 and wxPython 2.8.9.1

code fragment

   dlg=wx.MessageDialog(None,text,title,wx.YES_NO | wx.ICON_QUESTION)
   result=dlg.ShowModal()
#  result=wx.MessageBox(text,title,wx.YES_NO | wx.ICON_QUESTION)
   print 'result=',result,wx.ID_YES,wx.ID_NO

end code fragment