anchor.diff:              ?Debug("Guicnt != 0 ~p ~p", [autofilling,<<"more">>]),
               gui_append(#gres{state = autofilling, loop = <<"more">>, focus = -1}, State#state{stack = undefined, replyToFun=ReplyTo})
       end;
  -serve_stack(autofilling, #state{bufCnt=BufCnt,bufBot=BufBot,guiCnt=GuiCnt,guiBot=GuiBot,guiCol=GuiCol, stack = {button, <<">|">>, ReplyTo}} = State) ->
  +serve_stack(_SN, #state{bufCnt=BufCnt,bufBot=BufBot,guiCnt=GuiCnt,guiBot=GuiBot,guiCol=GuiCol, stack = {button, <<">|">>, ReplyTo}} = State) ->
       if
           (BufCnt == 0) -> State;                                    % no data, nothing to do, keep stack
           (BufBot == GuiBot) andalso (GuiCol == false) -> State;     % no new data, nothing to do, keep stack
  
positive.code:     State1 = data_append(filling, {Recs,false},State0),
      NewBufBot = State1#state.bufBot,
      NewGuiBot = State1#state.guiBot,
      State2 = if  
          (NewGuiBot == NewBufBot) -> prefetch(filling,State1);
          true ->                     State1
      end,
  
negative.code: serve_stack( _, #state{stack=undefined}=State) -> 
      % no stack, nothing .. do
      State;
  serve_stack(completed, #state{nav=ind,bufBot=B,guiBot=B,guiCol=true,stack={button,Button,RT}}=State0) when
        Button =:= <<">">>;
        Button =:= <<">>">>;
        Button =:= <<">|">>;
        Button =:= <<">|...">>;
        Button =:= <<"more">> ->
      ?NoDbLog(debug, [], "~p stack exec ~p when guiCol true", [completed,Button]),
      serve_bot(completed,<<>>,State0#state{stack=undefined,replyToFun=RT});
  serve_stack( _, #state{nav=ind,bufBot=B,guiBot=B}=State) -> 
      % gui is current at the end of the buffer, no new interesting data, nothing .. do
      State;
  