For other controls, there is an page in the help file for the localization of the control, listing the resource keys.
There is no such information for RadWindow.
Can you give us the resource keys?
RadWindow is localized through our LocalizationManager, this means that it provides built-in support for the following languages: English, German, Spanish, French, Italian, Dutch, Turkish.If the required language is not among them, you will need to manually translate the needed text and create a custom LocalizationManager. Here are the resource keys used by RadWindow:
Please, let me know if that answers your query.