GtkBuilder bug?

[Pavel Syomin <syomin radico ru>]

Hi, all!

I had been experimenting with GtkBuilder using Gtk+ 2.12.5 from Fedora 
8. I have found, that if there is reference to unknown type in UI-file, 
then application crashes. Is it a GtkBuilder bug?

Test program:
#include <gtk/gtk.h>

gint main(gint argc, gchar **argv)
{
       GtkBuilder *builder;

       gtk_init(&argc, &argv);

       builder = gtk_builder_new();
       gtk_builder_add_from_file(builder, "window.ui", NULL);

       return 0;
}

UI-file:
<interface>
 <object class="Unknown" id="window"/>
</interface>

Result:
[syomin syomin gtk-builder]$ ./a.out

Gtk-ERROR **: Invalid type: Unknown
aborting...
Segmentation fault