spinbutton_x->signal_activate().connect(sigc::mem_fun(*spinbutton_y,&Gtk::SpinButton::grab_focus));
distance_x->signal_activate().connect(sigc::mem_fun(*distance_y,&Gtk::SpinButton::grab_focus));
}
spinbutton_x->signal_activate().connect(sigc::mem_fun(*spinbutton_y,&Gtk::SpinButton::grab_focus));
distance_x->signal_activate().connect(sigc::mem_fun(*distance_y,&Gtk::SpinButton::grab_focus));
}