If I start a new project, it's fine, and everything works as expected.
No regular windows components are affected. Those I can still select with the mouse, even when they're in a RadForm.
I imagine there is a simple solution, but I can't figure it out.
Thanks
11 Answers, 1 is accepted

Thank you for writing to us. I am glad to hear that you managed to resolve the experienced issue.
Generally, all you need to do is to add a reference to the Telerik.WinControls.UI.Design dll and reopen the file you want to edit.
Alternatively, you can install the Telerik.WinControls.UI.Design.dll in your GAC (our installation does this automatically) which will allow Visual Studio to resolve the design-time implementation without any additional references.
I hope this helps.
All the best,
Ivan Petrov
the Telerik team

I can see you have opened another thread regarding the same matter, so I suggest that we keep this discussion there: http://www.telerik.com/community/forums/command-bar-dont-show-popup.
Regards,
Stefan
Telerik
Check out the Telerik Platform - the only platform that combines a rich set of UI tools with powerful cloud services to develop web, hybrid and native mobile apps.

Hi Stefan,
I am also facing the same issue. I am not able to select any controls(rad button, smart grid, etc) in design mode. Yesterday it was working. I am facing this issue today only. Kindly help.
Thank you for writing.
Usually, this happens after an upgrade, the following article shows how you can solve it: RadControls for WinForms are not loaded at design-time.
I hope this will be useful.
Regards,
Dimitar
Telerik by Progress

Thanks Dimitar. Some time its working and some time not. I have attached two different solution screenshot. I am able to select telerik controls in design mode of first solution. In 2nd solution I am not able to select. Kindly check the attached images.
I am using TFS for source management and SCSF framework for CAB design pattern. Kindly help.

Hi Dimitar,
I am using .NET 3.5 version and Telerik 2.0.
thanks & Regards,
Ramkumar
You should make sure that the assemblies referenced in your project have the same version as the ones installed on your system. When the suite is installed the Telerik.WinControls.UI.Design.dll assembly is added to the GAC and it is used for the design time functionality. The attached image shows how you can check which version is installed. Perhaps on of your solutions is using a different version.
I hope this helps. Should you have any other questions do not hesitate to ask.
Regards,
Dimitar
Telerik by Progress

Thanks Dimitar. Yes version is different.
Dll reference in project - 2010.2.10.928
Telerik reference installed in machine - 2010.2.10.914
Do I need to install "2010.2.10.928" in my machine?
Thank you for writing back.
Yes, you need to use install this version in order to use the Visual Studio designer. This way the assemblies installed in the GAC, used in the Visual Studio toolbox and referenced in the project will have the same version.
I hope this will be useful.
Regards,
Dimitar
Telerik by Progress