X functions doesn't working in the expose-event?

["Tom Liu" <tom liu flextrade com>]

Please help me to find the problem, when I use the x code to draw
something in the expose call back, the expose don't work.
The example is attatched, and the line shows up abut the rectangle will
not show automaticlly.
I need to use these x functions, to improve performance.
Thanks a lot.
------------------------------------------------------------------------
------------
        
#include <gtk/gtk.h>
#include "gdk/gdkx.h"

gint delete_event( GtkWidget *widget, GdkEvent  *event, gpointer   data
) {
    gtk_main_quit ();
    return FALSE;
}
static gboolean  boxitm_expos_cb (GtkWidget *w,GdkEventExpose
*event,gpointer cdat)
{
        GdkGC *m_gc=gdk_gc_new(w->window);
        gdk_draw_line(w->window,m_gc,0,0,100,100);
        XFillRectangle(GDK_DISPLAY(), GDK_WINDOW_XID(w->window),
GDK_GC_XGC(m_gc), 10,10,50,50);
        g_object_unref    (G_OBJECT(m_gc));
        return TRUE;
}

int main( int   argc, char *argv[] )
{
    GtkWidget *window;
    gtk_init (&argc, &argv);
    window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    g_signal_connect (G_OBJECT (window), "delete_event",
                      G_CALLBACK (delete_event), NULL);

    GtkWidget * ebox;
    ebox =gtk_drawing_area_new();
    g_signal_connect (G_OBJECT (ebox),
"expose-event",G_CALLBACK(boxitm_expos_cb),NULL);

    gtk_container_add (GTK_CONTAINER (window), ebox);
    gtk_widget_show_all (window);
    gtk_main ();
    return 0;
}