I haven't modified the project.
Telerik version is 2020.3.915.40
References(Telerik = 5) : Telerik.Windows.Controls, GridView, Input, Data
SDK settings are like this.
1. C:\Program Files (x86)\Progress\Telerik UI for WPF R3 2020\Binaries\WPF40
2. C:\Program Files (x86)\Progress\Telerik UI for WPF R3 2020\Binaries.NoXaml\WPF40
When just RUN in SDK, click the sort button and the window will just close.
That error is an error that appears when debugging in code.
When you click the sort button in your environment, the window does not close and there are no errors?