Please describe the problem:
I got this error from libglade when executing a program containing a message 
dialog with one button: 
 
libglade-WARNING **: could not find a parent that handles internal children for 
`vbox' 

Steps to reproduce:
1. Start new project
2. Create top level message dialog (see main.c)
3. Compile
4. Run


Actual results:
$ ./junk
(junk:5347): Gtk-WARNING **: Ignoring the separator setting

(junk:5347): libglade-WARNING **: could not find a parent that handles internal children for `vbox'
Message dialog opens but has no buttons

Expected results:
No warnings, message dialog with button.

Does this happen every time?
Yes

Other information:
main.c
------
#include <stdio.h>
#include <gtk/gtk.h>
#include <glade/glade.h>

GladeXML *gxml;

#define GLADE_FILE "junk.glade"

void on_messagedialog1_close (GtkWidget *w, gpointer user_data)
{
}

GtkWidget*
create_window (void)
{
        GtkWidget*      main_window;

        gxml = glade_xml_new (GLADE_FILE, NULL, NULL);

        main_window = glade_xml_get_widget (gxml, "messagedialog1");

        return main_window;
}

int
main (int argc, char *argv[])
{
        GtkWidget*      main_window;

        gtk_set_locale ();
        gtk_init (&argc, &argv);

        main_window = create_window ();
        glade_xml_signal_autoconnect (gxml);

        gtk_widget_show (main_window);

        gtk_main ();

        return 0;
}

Compile command
---------------
$  gcc -I/usr/include/libglade-2.0 -Wall -g -o junk main.c -export-dynamic `pkg-config --cflags --libs gtk+-2.0` -lglade-2.0

junk.glade
----------<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE glade-interface SYSTEM "glade-2.0.dtd">
<!--Generated with glade3 3.4.5 on Wed Dec 31 11:57:36 2008 -->
<glade-interface>
  <widget class="GtkMessageDialog" id="messagedialog1">
    <property name="border_width">5</property>
    <property name="resizable">False</property>
    <property name="window_position">GTK_WIN_POS_MOUSE</property>
    <property name="type_hint">GDK_WINDOW_TYPE_HINT_DIALOG</property>
    <property name="skip_taskbar_hint">True</property>
    <property name="has_separator">False</property>
    <property name="text">Message dialog</property>
    <property name="image"></property>
    <signal name="close" handler="on_messagedialog1_close"/>
    <child internal-child="vbox">
      <widget class="GtkVBox" id="dialog-vbox1">
        <property name="visible">True</property>
        <property name="spacing">2</property>
        <child internal-child="action_area">
          <widget class="GtkHButtonBox" id="dialog-action_area1">
            <property name="visible">True</property>
            <property name="layout_style">GTK_BUTTONBOX_END</property>
            <child>
              <placeholder/>
            </child>
            <child>
              <widget class="GtkButton" id="button1">
                <property name="visible">True</property>
                <property name="can_focus">True</property>
                <property name="receives_default">True</property>
                <property name="label" translatable="yes">button</property>
                <property name="response_id">0</property>
              </widget>
              <packing>
                <property name="position">1</property>
              </packing>
            </child>
          </widget>
          <packing>
            <property name="expand">False</property>
            <property name="pack_type">GTK_PACK_END</property>
          </packing>
        </child>
      </widget>
    </child>
  </widget>
</glade-interface>

$ uname -a
Linux steve.blackwell 2.6.26.5-28.fc8 #1 SMP Sat Sep 20 09:32:58 EDT 2008 i686 i686 i386 GNU/Linux