title: PyGTK ComboBox Not Visible
body: <p>I have a very simple PyGTK application that contains 1 widget - a ComboBox. For some reason the ComboBox is not visible when I run my python script. The main window is visible just not the ComboBox. Note I have successfully determined that the ComboBox exists and I have added it to the main window (added the widget to a box then added that to the main window).</p>
  
  <p>How can I get my ComboBox to appear?</p>
  
  <pre><code>import pygtk
  pygtk.require('2.0')
  import gtk
  
  
  class MainApp:
  
      def __init__(self):
          self.encryptFile = True
          self.window = gtk.Window(gtk.WINDOW_TOPLEVEL)
          self.window.connect("delete_event", self.delete_event)
          self.window.connect("destroy", self.destroy)
          main_box   = gtk.VBox(True, 10)
  
          client_store     = gtk.ListStore(str)
          self.clientFiles = ("a","b","c")
  
          for f in self.clientFiles:
              client_store.append([f])
  
          combobox        = gtk.ComboBox(client_store)
          renderer_text   = gtk.CellRendererText()
          combobox.pack_start(renderer_text, True)
          combobox.add_attribute(renderer_text, "text", 0)
          combobox.set_size_request(200,25)
  
          main_box.pack_start(combobox)
          main_box.show()
  
          self.window.add(main_box)
          self.window.show()
  
      def main(self):
          gtk.main()
  
      def delete_event(self, widget, event, data=None):
          return False
  
      def destroy(self, widget, data=None):
          gtk.main_quit()
  
  if __name__ == "__main__":
      app = MainApp()
      app.main()
  </code></pre>