As I mentioned previously, the problem is still observable with latest version of RadTreeView for Silverlight. The control is exactly the same in both the standard and the "Futures" version you listed. You can download the "Futures" one to play with the brand new Docking layout tool and RadGridView for Silverlight though. See this post
on the blogs for more details.
Let us know if you have any other questions.
All the best,
the Telerik team
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