title: Popup menu doesn't appear when clicking on StatusIcon
body: <p>I found that code on the Internet :</p>
  
  <pre><code>#!/usr/bin/env python3
  
  from gi.repository import Gtk
  
  def popup_menu(icon, button, time):
  
      menu = Gtk.Menu()
  
      menuitemAbout = Gtk.MenuItem(label="About")
      menu.append(menuitemAbout)
      menuitemQuit = Gtk.MenuItem(label="Quit")
      menu.append(menuitemQuit)
      menu.show_all()
  
      menu.popup(None, None, None, None, button, time)
  
  statusicon = Gtk.StatusIcon()
  statusicon.set_from_stock(Gtk.STOCK_HOME)
  statusicon.set_title("StatusIcon")
  statusicon.connect("popup-menu", popup_menu)
  
  window = Gtk.Window()
  window.connect("destroy", lambda q: Gtk.main_quit())
  window.show_all()
  
  Gtk.main()
  </code></pre>
  
  <p>A small menu should appear when I right-click on the status icon, but when I run the code and click, the menu appears and immediately disappears.</p>
  
  <p>Any idea why ?</p>