RadTreeView is not visible from Get Started help sample

[Gennady]

Output window just blank:
<telerik:RadTreeView> 
    <telerik:RadTreeView.Items> 
        <telerik:RadTreeViewItem Header="Football" /> 
        <telerik:RadTreeViewItem Header="Tennis" /> 
        <telerik:RadTreeViewItem Header="Cycling" /> 
        <telerik:RadTreeViewItem Header="Basketball" /> 
    </telerik:RadTreeView.Items> 
</telerik:RadTreeView
Did add "standard" TreeView control and it is showing fine.
What i'm missing in Getting Started Sample?
https://docs.telerik.com/devtools/wpf/controls/radtreeview/getting-started/getting-started
Thank you,
Gennady

[Martin Ivanov]

Hello Gennady,

This type of issues are described the Missing Controls in the UI help article. Can you check it out and see if it helps?

Regards,
Martin Ivanov
Progress Telerik

[Gennady]

Yes, Martin,

I was using non-xml Telerik dll's. Adding resources in xaml solved the problem.

Thank you!