Any time you right the ItemsSource with the proper benefit XAML doesn't automatically reilitialize the gathering of things. So your DataContext for "video_length_textbox" is set to itself, and also your IncrementingTextBox class doesn't have a public property termed ConfigurationModel Granted, it can help (marginally) to refactor code Down the road, https://amrapaliprojectsinnoida.blogspot.com/2025/05/shape-your-future-with-modern-elegance.html