I am not sure what you mean by created in the xaml RadWindow. If you mean that you have a UserControl that is of RadWindow type and you are settings its properties in the xaml, in order to set the icon you will need to set it like this:
I attached a sample project and a short video for you showing that the icon is set correctly after pinning the RadWindow to the taskbar. Hope this is helpful.
TRY TELERIK'S NEWEST PRODUCT - EQATEC APPLICATION ANALYTICS for WPF.
Learn what features your users use (or don't use) in your application. Know your audience. Target it better. Develop wisely.
Sign up for Free application insights >>