Hi Vien Nguyen,
There is a known problem which occurs when a Silverlight project is assigned as startup instead of a Web project. In this case the tiles are displayed in design time and are not displayed at runtime, because the security policies do not allow downloading data from Web.
You should create a Web project which will be used to run your Silverlight application (if Visual Studio didn’t do it for you) and set it as startup project. Usually Visual Studio asks you to create that project when you create Silverlight solution.
If this is not the case, I am afraid we can't help you with this problem without seeing your code. Could you, please, create a sample solution which demonstrates things you are trying to implement and send it to us?
the Telerik team
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