Can any one help me with this

i have a panel where i populate dynamic rows, so i have given auto height for it but after 300 or 400 i have to give scroll for it

i think autoHeight :true over ride max height and auto Scroll

so is there any way to get wat i seek?

Code:
this.searchcriteriapanel=new Ext.Panel({ 
            id:'searchPanel', 
            frame:true, 
            border:false, 
            autoHeight:true,
            maxHeight:300, 
            autoScroll:true, 
            split:false, 
            width:565, 
            layout:'form', 
            itemCls: 'floatLeft'

})