怎么在WebBrowser控件 当中设置不保存浏览记录

procedure TForm3.Button2Click(Sender: TObject);
var  url,   flags, TargetFrame, postdata, headers:olevariant;
begin

  {navOpenInNewWindow = $00000001;
  navNoHistory       = $00000002;
  navNoReadFromCache = $00000004;
  navNoWriteToCache  = $00000008;
  navAllowAutosearch = $00000010;
  navBrowserBar      = $00000020;   }

     flags:=navNoWriteToCache   or   navNoHistory;
     WebBrowser1.Navigate('http://www.163.com'，flags);     

end;

我已经设置了flags:=navNoWriteToCache   or   navNoHistory;
为什么 还是有历史记录呢？

还要设置那里呢？