let make

  ~(generator: ((string,string) env)->(string list)) 
      (** The option generator. May be a constant function as particular case. *)

  ~(msg:(string,string) env)                         
                            (** The input for the generator. *)

  ~(key:string)                                      
                                        (** The key of the pair (key,value) send to its childs. *)

  ~(callback:(choice->unit) option)                  
                     (** An optional callback function, to call at any change *)

  ~(packing:(GObj.widget -> unit) option)            
                 (** The packing function. *)
      
 
    = let self = new comboTextTree ~generator ~msg ~key ~callback ~packing in
      let _ = self#initialize_callbacks in self