Regarding you first request you could set Width and Height to the control. In case that the embedded tree has bigger dimensions scroll bars will appear. We also planning to create AutoWidth option.
The filtering is also in our TODO list. Now we use back slash
as a separator so, we need to export it as a property for the upcoming releases.
the Telerik team
If you want to get updates on new releases, tips and tricks and sneak peeks at our product labs directly from the developers working on the RadControls for ASP.NET AJAX, subscribe to their blog feed