root = new GLtk::Root(ui_res, window);
root->signal_button_press.connect(sigc::mem_fun(this, &Engineer::button_press));
root->signal_pointer_motion.connect(sigc::mem_fun(this, &Engineer::pointer_motion));
root = new GLtk::Root(ui_res, window);
root->signal_button_press.connect(sigc::mem_fun(this, &Engineer::button_press));
root->signal_pointer_motion.connect(sigc::mem_fun(this, &Engineer::pointer_motion));