struct app_frame : ... {
app_frame();
int show_label;
};
app_frame::app_frame() {
set_cmd_chooser(&app_frame::show_label,this)
.for_id(ID_label_left, 1)
.for_id(ID_label_center, 2)
.for_id(ID_label_right, 3);
// initially set it to "Left" state
show_label = 1;
}