Bug 2698

That change was part of a bug fix.
I've prepared a simple example to test this:

uses Chart, Series, TeeTools;

var Chart1: TChart;

procedure TForm1.FormCreate(Sender: TObject);
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;

    with TPointSeries(AddSeries(TPointSeries)) do
    begin
      FillSampleValues(100);
      Pointer.Size:=2;
    end;

    with TColorBandTool(Tools.Add(TColorBandTool)) do
    begin
      Axis:=Axes.Bottom;
      StartValue:=20;
      EndValue:=70;
      //StartLine.NoLimitDrag:=True;
      //EndLine.NoLimitDrag:=True;
    end;
  end;
end;

Note the NoLimitDrag property of the TColorLineTool(s) inside the TColorBandTool, which is False by default.
Before v2023.38 setting those NoLimitDrag properties to False/True made no difference, and you could still drag the ColorBand out of the chart without limits.
From TeeChart v2023.38, NoLimitDrag property is considered. As per default, False, those ColorLine values are limited to the bounds of the chart. However, setting the NoLimitDrag property to True does change that behaviour, and you can   drag outside the chart bounds without limits.