title: wxPython BusyInfo widget no longer works
body: <p>In my wxPython GUIs, the wx.BusyInfo widget no longer works.  I'm working on OSX, and I recently upgraded to El Capitan. </p>
  
  <p>This simple code below doesn't work anymore with either of the wx versions that I have available ('3.0.2.0' or '2.9.2.4').  As far as I can tell, wx.BusyInfo simply no longer shows up.  Unfortunately, I don't know exactly when the widget stopped appearing.  </p>
  
  <pre><code>class MyFrame(wx.Frame):
  
      def __init__(self, parent, title):
          super(MyFrame, self).__init__(parent, size=(450, 350))
          self.panel = wx.Panel(self)
  
          btn = wx.Button(self.panel, wx.ID_ANY, "Do thing")
          self.Bind(wx.EVT_BUTTON, self.do_thing)
          self.Centre()
          self.Show()
  
      def do_thing(self, event):
          wait = wx.BusyInfo('Please wait...')
          time.sleep(5)
          del wait
  </code></pre>
  
  <p>Any ideas on the cause or solution to this problem?  </p>