I am creating an app with a button which is on the window with a pixmap.
 gtk-init (&argc, &argv); 
 window = gtk_window_new 
(GTK_WINDOW_TOPLEVEL);
 gtk_window_set_title (GTK_WINDOW (window), "MPI 
Company Ltd."); 
 gtk_signal_connect (GTK_OBJECT (window), 
"destroy", GTK_SIGNAL_FUNC (gtk_exit), 
NULL); 
 gtk_container_border_width (GTK_CONTAINER (window), 
5); 
 style = gtk_widget_get_style(parent); 
 pixmap = 
gdk_pixmap_create_from_xpm (window, &mask,
    
     &style->bg[GTK_STATE_NORMAL],&file);    
     
 pixmapwid = gtk_pixmap_new (pixmap, 
mask);
 button = gtk_button_new_with_label 
("beautiful");
 gtk_signal_connect (GTK_OBJECT (button), 
"clicked",
                        
GTK_SIGNAL_FUNC (callback), (gpointer) "beautiful");
 gtk_container_add 
(GTK_CONTAINER (pixmapwid), 
button); 
 gtk_widget_show(button); 
 gtk_container_add 
(GTK_CONTAINER (window), pixmapwid);
 gtk_widget_show 
(pixmapwid);   
gtk_widget_show(window); 
 gtk_main 
();
 When I app it, I get this:
Gtk-CRITICAL **: file 
gtkcontainer.c: line 712 (gtk_container_add): 
assertion
GTK_IS_CONTAINER(container) ' failed.
The button doesnot ON the pixmap!WHY?
How could I solve this?
weiwu