Thank you for writing.
This forum discusses the grid control for WinForms: https://docs.telerik.com/devtools/winforms/gridview/overview
. We do not have a FilterRow mode for the textbox column. I am assuming that you might be using the RadGridView control for WPF. If that is really the case post your question in the WPF forum, here: https://www.telerik.com/forums/wpf/gridview
Let me know if you have other questions.