The following program segfaults with gtkmm 1.3.23:

#include <gtkmm.h>

class WindowWithMenuBar: public Gtk::Window {
public:
    Gtk::MenuBar menubar_;
    
    WindowWithMenuBar () {
        add(menubar_);
    }
};


class AnotherWindow: public WindowWithMenuBar {
public:
    Gtk::Menu menu_foo_;

    AnotherWindow () {
        menubar_.items().push_back(
                Gtk::Menu_Helpers::MenuElem("Foo", menu_foo_));
    }
};


int main (int argc, char *argv[])
{
    Gtk::Main kit(argc, argv);
    AnotherWindow w;
    kit.run(w);
}

This program runs without problems if you combine the two classes.