Hi Web Services,
Thank you for the provided code and live url, I examined the page and I was able to reproduce the problem. However, I was not able to completely understand the reason for it without examining it locally. By analyzing the page with the IEDevToolBar I saw that the scrolling of the panes is enabled and I believe that the problem does not come from them.
I attached the sample demo which I built based on your code - as you can see there, when you expand the root node, more nodes are shown and a scrollbar is generated. I would like to kindly ask you to modify my demo in order to reproduce the problem, open a new support ticket and send it to me. That will make me able to investigate further the layout and I will do my best to help.
On a side note, I also suggest to examine the following KB article, which demonstrates how to make the splitter resize according to its content:
If you choose this approach, uyou can resize the splitter when the treeview node is clicked and you should just enable the scrolling on the page by removing your CSS which disables it and the browser scrollbars will be generated after the splitter resizes.
All the best,
the Telerik team