Please describe the problem:
Reusing the same GtkFileChooserWidget multiple times sends error messages to the concole.

Steps to reproduce:
Run:

GtkWidget *window;
GtkWidget *file_widget;
gboolean delete_event(GtkWidget *widget, GdkEvent *event, void *)
{
    if(GtkWidget *sub = gtk_bin_get_child(GTK_BIN(window)))
        gtk_container_remove(GTK_CONTAINER(window), sub);
    else
        gtk_container_add(GTK_CONTAINER(window), file_widget);
    return TRUE;
}


int main()
{
window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
file_widget = gtk_file_chooser_widget_new(GTK_FILE_CHOOSER_ACTION_SAVE);
g_object_ref(file_widget);
g_signal_connect(G_OBJECT(window), "delete_event", 
G_CALLBACK(delete_event), 0);
gtk_container_add(GTK_CONTAINER(window), file_widget);
gtk_widget_show_all(window);
gtk_main();
return 0;
}


Actual results:
Console shows messages like:

(DiamondBOX:18575): Gtk-CRITICAL **: gtk_tree_model_get_iter: assertion 
 `path != NULL' failed

 (DiamondBOX:18575): Gtk-CRITICAL **: gtk_list_store_set_valist: 
 assertion `VALID_ITER (iter, list_store)' failed

 (DiamondBOX:18575): Gtk-CRITICAL **: gtk_tree_model_get_iter: assertion 
 `path != NULL' failed

 (DiamondBOX:18575): Gtk-CRITICAL **: gtk_list_store_set_valist: 
 assertion `VALID_ITER (iter, list_store)' failed

 (DiamondBOX:18575): Gtk-CRITICAL **: gtk_tree_model_get_iter: assertion 
 `path != NULL' failed

 (DiamondBOX:18575): Gtk-CRITICAL **: gtk_list_store_set_valist: 
 assertion `VALID_ITER (iter, list_store)' failed


Expected results:
Nothing

Does this happen every time?
Yes

Other information: