void on_size_request (Gtk::Requisition* req);
void on_size_allocate (Gtk::Allocation&);
void on_style_changed (const Glib::RefPtr<Gtk::Style>&);
void on_size_request (Gtk::Requisition* req);
void on_size_allocate (Gtk::Allocation&);
void on_style_changed (const Glib::RefPtr<Gtk::Style>&);