title: PyGTK entry.set_placeholder_text doesnt work - missing tex
body: <p>I am attaching a piece of my code in which I try to display the text in the Entry field with predefined text. I use entry.set_placeholder_text for this, but unfortunately the text does not appear.
  Is there an effective solution?</p>
  <pre class="lang-py prettyprint-override"><code># -*- coding: utf-8 -*-
  import gi
  gi.require_version(&quot;Gtk&quot;, &quot;3.0&quot;)
  from gi.repository import Gtk
  
  class MyWindow(Gtk.Window):
      def __init__(self):
          super(MyWindow, self).__init__()
          entry = Gtk.Entry()
          entry.set_placeholder_text(&quot;Any text&quot;)
          self.add(entry)
  
  win = MyWindow()
  win.connect(&quot;destroy&quot;, Gtk.main_quit)
  win.show_all()
  Gtk.main()
  </code></pre>