anchor.diff:    FOptScrollMarkSizeX:= 20;
     FOptScrollMarkSizeY:= 4;
   
  +  FOptShowAtBottom:= false;
     FOptShowScrollArrows:= true;
     FOptShowScrollMark:= true;
     FOptShowDropMark:= true;
  
positive.code:   if IsClick then     
    begin
      DoHandleClick;
      Exit
    end;
  end;
  
negative.code:   if TabCount>0 then
    begin
      D:= GetTabData(TabCount-1);
      Result:= Max(0,
        D.TabRect.Right - RDown.Left +
        IfThen(FOptShowPlusTab, GetTabRectWidth(true))
        );
    end;
  end;
  
  