Eso es por que no estas mostrando la ventanita.
Código Python:
Ver originalimport pygtk
import gtk
from gtk import glade
s = """<?xml version="1.0" encoding="UTF-8"?>
<glade-interface>
<!-- interface-requires gtk+ 2.8 -->
<!-- interface-naming-policy project-wide -->
<widget class="GtkWindow" id="window1">
<property name="default_width">440</property>
<property name="default_height">250</property>
<child>
<placeholder/>
</child>
</widget>
</glade-interface>"""
pygtk.require('2.0')
wTree = glade.xml_new_from_buffer(s, len(s))
window = wTree.get_widget("window1")
window.connect("destroy", gtk.main_quit)
window.show()
gtk.main()