anchor.diff:    if FSliderPos > area then
       FSliderPos := area;
   
  -  if ppos <> FSliderPos then
  -    DrawSlider(False);
  -
     if area <> FMin then
       newp := FMin + Trunc((FMax - FMin)  * (FSliderPos / area))
     else
  
positive.code:   if newp <> FPosition then
    begin
      Position := newp;
      if Assigned(FOnChange) then
        FOnChange(self, FPosition);
    end;
  
negative.code:   r: TfpgRect;
    tw: TfpgCoord;
  begin
    Canvas.Clear(FBackgroundColor);
    Canvas.SetColor(FBackgroundColor);
  
  