Thank you for contacting us.
Reviewing the details that you provided us, I suppose the reason why you could not access Telerik UI for ASP.NET AJAX
in the Visual Studio Toolbox
is that the current version of the toolbox controls mismatch the target framework of the project.
In order to get access to the UI for ASP.NET AJAX
toolbox controls in your project, you just need to choose the appropriate controls version. For example: when you have project with .NET 4.0 target framework, the version of the controls should be for .NET 4.0 Framework.
Changing the controls versions could be done using our Toolbox Configurator
wizard. More information about the wizard and how to use it can be found on this: LINK
Should you have additional questions or need further assistance, do no hesitate to get back to us.
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