使用自动完成扩展程序时消失滚动条

I use the Autocomplete extender feature to get the list of suggestions from my database. There is no scroll bar for this control, so I have added a scroll bar in a panel (MS .net 2.0) which i attach to my autocomplete extender.Now the issue is with the srcoll bar. like this I use the Autocomplete extender feature to get