scrollbar missing in treepanel

[pailyanish]

hai

i have two treepanel on the first treepanel i have set 'autoscroll:true' so the scrollbar is coming.my second treepanel is dynamically generated on clicking the checkbox on first treepanel. my problem is i have given 'autoscroll:true' in my second treepanel in this
scroll is working but the scroll bar is missing.

i have given this two treepanel in a formpanel with Layout:'fit'

i am attaching a screenshort

can anyone helpme to sort this out

thanks in advance

[Animal]

Javascript is case sensitive.

http://www.extjs.com/deploy/ext-3.0.0/docs/?class=Ext.Panel&member=autoScroll