title: Python Gtk.MessageDialog Hides Parent Window
body: <p>I am working on a Gtk3 app written in Python. The main window for my app is set up as follows:</p>
  
  <pre><code>#!/bin/python
  import gi
  gi.require_version('Gtk', '3.0')
  
  from gi.repository import Gtk as Gtk
  
  ## OTHER IMPORTS
  
  class MainGui(Gtk.Window):
      def __init__(self):
          Gtk.Window.__init__(self, title="APP TITLE")
  
          # Defaults
          self.set_default_size(600, 500)
  
          ## OTHER CODE            
  
          # Setup the Window
          self.connect("destroy", self.on_close)
          self.show_all()
  
      ## OTHER CODE    
  
      def on_close(self, widget):
          if self.editor.get_document().get_has_changes():
              save_dialog = Gtk.MessageDialog(self, 0,
                  Gtk.MessageType.QUESTION,
                  Gtk.ButtonsType.YES_NO,
                  "Save changes?")
              response = save_dialog.run()
  
              ## REST OF DIALOG HANDELING
  </code></pre>
  
  <p>The problem I'm having is related to the save dialog. The app displays the dialog just fine, but it hides my main window, which is not the desired effect. I've tried searching around for a solution, but can't seem to figure out what I'm doing wrong. Any help would be greatly appreciated!</p>