anchor.diff:      function GetTabRect(AIndex: integer): TRect;
       function GetTabRect_Plus: TRect;
       function GetTabRect_X(const ARect: TRect): TRect;
  -    function GetTabAt(X, Y: integer): integer;
  +    function GetTabAt(X, Y: integer; out APressedX: boolean): integer;
       function GetTabData(AIndex: integer): TATTabData;
       function TabCount: integer;
       procedure AddTab(
  
positive.code: end;
  
  
  function TATTabs.GetTabAt(X, Y: integer): integer;
  var
    i: integer;
    Pnt: TPoint;
    R1: TRect;
  begin
    Result:= -1;
    Pnt:= Point(X, Y);
  
    if PtInRect(FRectArrowLeft, Pnt) then
  
negative.code: 
  procedure TATTabs.MouseDown(Button: TMouseButton; Shift: TShiftState;
    X, Y: integer);
  var
    IsX: boolean;
  begin
    FMouseDown:= Button in [mbLeft, mbMiddle]; //but not mbRight
    FMouseDownRightBtn:= (Button = mbRight);
  