There is a limitation in Visual Studio 2010 Beta2 we identified recently: The design time of RadControls for ASP.NET AJAX is not working properly and the intellisense is broken in a standard setup (having the Telerik.Web.UI assembly in the website bin folder).
While we are working together with Microsoft for having this fixed, here are two workarounds:
1. You won't get the design time or the intellisense broken if you perform these two steps when closing your project in VS2010:
- Open a page, containing a RadControl in design mode (ignore the design mode errors);
- Close the IDE. The next load of the solution in Visual Studio 2010 should open the page in design mode again, but the designers should be loaded successfully and the intellisense should be working properly.
2. Add the Telerik.Web.UI assembly to the GAC or copy it to the [VisualStudioInstallDir]\Common7\IDE\PrivateAssemblies folder. The Visual Studio IDE would load the Telerik.Web.UI assembly properly.
The Telerik team