About Gtk::Bin?

["BC Zhu" <zhubicen gmail com>]

I was wondering the reason why the following code cann't work? It
shows nothing, i expect it can show one button.
How to fix this issue?
Thanks in advance.

#include <gtkmm.h>
#include <gtkmm/main.h>
#include <gtkmm/window.h>
class Viewer:public Gtk::Bin
{
public:
    Viewer():table_(2, 2), button_("ZHU"){
        table_.attach(button_, 0, 1, 0, 1);
        show_all_children();
    }
private:
    Gtk::Table table_;
    Gtk::Button button_;
};
class Window:public Gtk::Window
{
public:
    Window(){
        add(viewer_);
        viewer_.show();
    }
private:
    Viewer viewer_;
};
int main (int argc,char *argv[])
{
    Gtk::Main kit(argc, argv);
    Window win;
    Gtk::Main::run(win);
    return 0;
}






-- 
Best Regards
Bicen.Zhu