To achieve your requirement you can extract the style
of the dialog
you are using (RadConfirm or RadPrompt) and modify it a bit. Basically, you can set the Content property of the OK and Cancel buttons to match the Yes and No words, and also include an additional button for the "Do not remember again" option. I prepared a small example showing this approach. I hope that helps.
As I can see you already found the feature request for introducing an additional button to the template of the dialog, but I am posting it also here - https://feedback.telerik.com/Project/143/Feedback/Details/113627-window-make-it-possible-to-add-no-button-to-the-confirm-dialog-without-the-nee
Want to extend the target reach of your WPF applications, leveraging iOS, Android, and UWP? Try UI for Xamarin
, a suite of polished and feature-rich components for the Xamarin framework, which allow you to write beautiful native mobile apps using a single shared C# codebase.