Hi Alex Olenev,

When you create a new RadTreeView control it always gets its default style and ControlTemplate from the Office_Black theme. You can however, implement your own custom style/ControlTemplate for the RadTreeView. When you create a custom implicit style (without x:Key) for the control and you place it in your application resources, then this style will be applied to all RadTreeView controls throughout the application.

You can also create your own theme for the control based on any of the built-in Telerik themes.

I hope that info helps. Please let me know if I can further assist you.

Greetings,
Tina Stancheva
the Telerik team