anchor.diff:  {----------------THtmlViewer.HTMLMouseWheel}
   
   procedure THtmlViewer.HTMLMouseWheel(Sender: TObject; Shift: TShiftState;
  -  WheelDelta: Integer; MousePos: TPoint);
  +  WheelDelta: Integer; MousePos: TPoint; var Handled: Boolean);
   var
     Lines: Integer;
   begin
  
positive.code:       VScrollBarPosition := VScrollBarPosition + (Lines * 16)
    else
      VScrollBarPosition := VScrollBarPosition - WheelDelta div 2;
  end;
  
  function THtmlViewer.DoMouseWheel(Shift: TShiftState; WheelDelta: Integer;
    MousePos: TPoint): Boolean;
  begin
    result := inherited DoMouseWheel(shift, wheelDelta, mousePos);
    if not result and not (htNoWheelMouse in htOptions) then
    begin
      HTMLMouseWheel(Self, Shift, WheelDelta, MousePos);
      Result := True;
    end;
  end;
  
   {----------------THtmlViewer.XYToDisplayPos}
  
negative.code:   PaintPanel.OnMouseDown := HTMLMouseDown;
    PaintPanel.OnMouseMove := HTMLMouseMove;
    PaintPanel.OnMouseUp := HTMLMouseUp;
    PaintPanel.OnMouseWheel := HtmlMouseWheel; // BG, 25.09.2012: issue 174. Thanks to Alan Chate
  
    VScrollBar := TScrollBar.Create(Self);
    VScrollBar.Kind := sbVertical;
  