Trouble with GtkUIManager

[Doug Baldwin <baldwin geneseo edu>]

	Trying to learn about GtkUIManager, and running into a strange  
behavior. As an initial experiment, I'm trying to create a menu bar  
containing only one menu, which in turn contains only one menu item.  
This menu bar is the only element in my top-level window. The code (C+ 
+) is as follows:

int main (int argc, char* argv[]) {

    gtk_init( &argc, &argv );


    // Create top-level window and arrange to stop the program when  
it closes.

    GtkWidget* window = gtk_window_new( GTK_WINDOW_TOPLEVEL );
    g_signal_connect( window, "delete-event",  
reinterpret_cast<GCallback>(closeMainWindow), NULL );


    // Create the UIManager.

    static const gchar* const menuDef =
         "<ui>\
            <menubar name=\"Menus\">\
                <menu name=\"File\" action=\"FileMenuAct\">\
                    <menuitem name=\"Quit\" action=\"QuitAct\"> </ 
menuitem>\
                </menu>\
            </menubar>\
         </ui>";

    static const GtkActionEntry acts[] = { { "FileMenuAct", NULL,  
"_File" },
                                                                      
{ "QuitAct", GTK_STOCK_QUIT, "_Quit", "<control>Q", "Exit this program",
                                                                        
 reinterpret_cast<GCallback>(menuShutdown) } };
    const guint nActs = 2;

    GtkActionGroup* menuActions = gtk_action_group_new 
( "MenuActions" );
    gtk_action_group_add_actions( menuActions, acts, nActs, NULL );

    GtkUIManager* menuManager = gtk_ui_manager_new();
    gtk_ui_manager_insert_action_group( menuManager, menuActions, 0 );

    GError* menuError = 0;
    const guint mergeID = gtk_ui_manager_add_ui_from_string 
( menuManager, menuDef, -1, &menuError );
    if (  mergeID == 0  ||  menuError != 0  ) {
        cerr << "Error: Failed to add menu definitions to menu UI  
manager -- " << menuError->message << endl;
        g_error_free( menuError );
    }

    gtk_ui_manager_ensure_update( menuManager );

    GtkWidget* menuBar = gtk_ui_manager_get_widget( menuManager, "/ 
Menus" );
    gtk_container_add( reinterpret_cast<GtkContainer*>(window),  
menuBar );


    // Make everything visible.

    gtk_widget_show_all( window );

    gtk_main();

    return 0;
}

When I run this code, no window appears at all. If I remove the  
"gtk_container_add" that adds the menu bar to the main window, the  
program displays an empty window as I would expect it to. I'm using  
GTk+2 2.6.10 on Mac OS X 10.4.11, running the above program under the  
X11 that came with the Mac (which identifies itself as X11 1.1.3 -  
XFree86 4.4.0). Does anyone have any thoughts about what I'm doing  
wrong? Thanks.