Thank you for writing.
You can achieve this task by removing the ReadOnly
setting for the grid and for the details column. Please note that we have an updated example in our demo application. It gets automatically installed together with our suite. The source code of the examples is located in the installation folder of the controls with the default location being: C:\Program Files (x86)\Telerik\UI for WinForms Q1 2015\Examples\QuickStart\GridView.
I have also prepared a small example which can serve as a starting point and should get you going.
Besides my project I am also sending you a screenshot of the result on my side.
I hope this helps. Should you have further questions please do not hesitate to write back.