anchor.diff:  constructor TTreeViewMy.Create(AOwner: TComponent);
   begin
     inherited;
  -  ScrollBars:= ssNone;
   
     FScroll:= TATScroll.Create(Self);
     FScroll.Parent:= Self;
  
positive.code:     function DoMouseWheel(Shift: TShiftState; WheelDelta: Integer; MousePos: TPoint): Boolean; override;
    public
      constructor Create(AOwner: TComponent); override;
      property Themed: boolean read FThemed write FThemed;
    end;
  
  const
  
negative.code:     FScroll: TATScroll;
      FThemed: boolean;
      procedure ScrollChange(Sender: TObject);
      procedure SetThemed(AValue: boolean);
      procedure UpdScroll;
    protected
      procedure DoSelectionChanged; override;
  