Please accept our apologies for the delayed response.
Unfortunately we wasn't able to reproduce the described issue. I copied the provided code snippet in the Blend and there wasn't such an error. And the RadTileView is rendered properly.
What is the version of Blend you are using?
What is the version of our controls used?
We will really appreciate if you can send us your project in order to identify the problem.
All the best,
the Telerik team
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