Hello Mark, 

The feedback item status is changed to Declined due to inactivity.

Regards,
Dinko | Tech Support Engineer
Progress Telerik

Hello, Mark,

I am really sorry to hear that you are experiencing any difficulties with RadGridView from the Telerik UI for WinForms suite. However, the provided limited information is not enough for me to replicate the issue locally or make an adequate analysis of the precise case. That is why it would be greatly appreciated if you can provide more details about the grid's setup or what changes/steps lead to the duplicated rows. A sample video illustrating the unexpected behavior would be very helpful as well.

I understand that it is difficult to isolate the problem in a sample application, however, a sample runnable project, demonstrating the exact undesired behavior that you are facing, may save a lot of days and efforts on both sides. That is why it is always greatly appreciated if you simulate the problematic behavior in a runnable project. Then, we would be able to make an adequate analysis of the precise case and think about a suitable solution. This is the most important thing you can do to clearly demonstrate your issue. Replicating your issue is no doubt the most time consuming part, but it's going to play the biggest role in your success at demonstrating your issue clearly the first time. 

Thank you in advance for your cooperation. I am looking forward to your reply.

Regards,
Dess | Tech Support Engineer, Principal
Progress Telerik