GTK_WINDOW_POPUP assertion fails

[Andrew Hogue <ergo secondthought org>]

Hello -

I am working with GTK 1.2.10, on Linux 2.4.18 (Red Hat 9.0).  I am 
attempting to create a GTK window through the JNI (see code attached 
below), and I receive the following assertion failure during execution:

(<unknown>:6338): Gtk-CRITICAL **: file gtkwindow.c: line 794 
(gtk_window_new): assertion `type >= GTK_WINDOW_TOPLEVEL && type <= 
GTK_WINDOW_POPUP' failed

A series of other assertions subsequently fail, all seemingly because 
*mShell is null.

I'm creating the window with:

    static GtkWidget *mShell = NULL;
    [snip]
    mShell = gtk_window_new (GTK_WINDOW_POPUP);

Why does this assertion fail?

Thanks in advance!

-Andrew Hogue

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
GtkMozEmbed.cpp
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
#include <jni.h>
#include "GtkMozEmbed.h"

#include <jawt_md.h>
#include <jawt.h>

#include <X11/Xlib.h>

#include <gdk/gdkx.h>
#include <gtk/gtk.h>
#include "gtkmozembed.h"

#include "nsGtkEventHandler.h"

#include <dlfcn.h>


/*
 * Class:     org_eclipse_swt_widgets_GtkMozEmbed
 * Method:    createTopLevelWindow
 * Signature: ()I
 */
JNIEXPORT jint JNICALL 
Java_org_eclipse_swt_widgets_GtkMozEmbed_createTopLevelWindow
(JNIEnv * env, jobject obj) {

    static GtkWidget *mShell = NULL;

    /* Initialise GTK */
    gtk_set_locale ();
    gtk_init (0, NULL);
    gdk_rgb_init();
    mShell = gtk_window_new (GTK_WINDOW_POPUP);
    gtk_window_set_default_size(GTK_WINDOW(mShell), 300, 300);
    gtk_window_set_title(GTK_WINDOW(mShell), "Simple browser");
    return (jint) mShell;
}