Created attachment 1056 [details]
screenshot

Having stacked bars and mouse hover active, when you move the mouse over a mark, two bars are highlighted: the bar related to the mark, and the bar in the back.

Simple example:

uses Chart, TeEngine, Series;

var Chart1: TChart;

procedure TForm1.FormCreate(Sender: TObject);
var s, v: Integer;
begin
  Chart1:=TChart.Create(Self);

  with Chart1 do
  begin
    Parent:=Self;
    Align:=alClient;
    Color:=clWhite;
    Gradient.Visible:=False;
    Walls.Back.Color:=clWhite;
    Walls.Back.Gradient.Visible:=False;
    //Legend.Hide;
    View3D:=False;
  end;

  for s:=0 to 2 do
    with TBarSeries(Chart1.AddSeries(TBarSeries)) do
    begin
      Title:='Long title for Series'+IntToStr(s);
      MultiBar:=mbStacked;
      Marks.Style:=smsSeriesTitle;

      for v:=0 to 3 do
      begin
        if ((s=0) and (v=1)) or
           ((s=1) and (v=2)) then
        begin
          AddNull();
          Continue;
        end;

        Add(5+random*5, IntToStr(v));
      end;
    end;
end;