The most common reason for such behaviour is if the UI virtualization functionality of RadGridView has been disabled due to the fact that the control is placed in a container that measures its children in an infinite size. You can learn more about this functionality in this help topic
. In case this is not the cause for the issue on your end, please take a look at the Degraded Performance
help topic on our documentation to see if one of the suggestions in it will help.
If none of the suggestions in the article help, we'd appreciate a sample application demonstrating the degrading performance that we can troubleshoot on our end.
Do you want to have your say when we set our development plans? Do you want to know when a feature you care about is added or when a bug fixed? Explore the Telerik Feedback Portal
and vote to affect the priority of the items