RadDocking for Silverlight/WPF is quite different than RadDock for ASP.NET - the Silverlight control is intended to create desktop-like interfaces similar to Visual Studio, while the ASP.NET control is used to create web intefraces similar to iGoogle.
You can browse the demos of RadDocking for Silverlight here:
As for your questions:
1) RadDocking for Silverlight is able to contain only Silverlight content (controls and media). You could use RadHtmlPlaceholder control to put HTML inside RadDocking, but this approach has a lot of limitations and I would strongly recommend not doing it.
2) No. The controls were designed to solve different problems and have different API.
3) Please, check the online demos first, to understand what can be done with the control and then if you need specific example, we will gladly provide you with such.
the Telerik team
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