[gtkmm] Centering Gnome::UI::About dialog

[Bo Majewski <bo majewski com>]

Is there a simple way to center the Gnome::UI::About dialog with respect
to the top level window? I could not find an appropriate explanation in
the documentation ... consequently I am doing

    if (!about) {
	about = new Gnome::UI::About(PACKAGE, 
		  		     VERSION,
                                     .. // etc., and so on
				     icon);
	
	about->set_icon(icon);
    }
    
    about->show();

but this way the dialog appears centered on the screen and not with the
respect to the top level window.

Bo