Thanks for writing and please, excuse me for the late reply.
It is possible to experience such a problem if you don't have the Telerik.WinControls.UI.Design, v. 2011.3.11.1116 assembly installed in the GAC. The design assembly is responsible for the proper rendering of the RadControls for WinForms in the Designer.
Could you please check if the assembly Telerik.WinControls.UI.Design, v. 2011.3.11.1116 is installed in the GAC on your machine?
If the assembly is missing, please follow the steps below:
- Add Telerik.WinControls.UI.Design, v. 2011.3.11.1116 to the GAC
- Restart Visual Studio
- Drag a control and check if the designer is working
The design assembly comes along with the distribution of control assemblies. If the distribution was downloaded through the Visual Studio extensions it can be found in %APPDATA%\Telerik\Updates
I hope this will help you in solving this issue.
the Telerik team