Currently the Danish resource file contains the original English Scheduler messages as there are no native Danish speakers on our side. For more information about how to modify the build-in resource files you can check the following help article:
Another option is to use the "Messages" option of the Scheduler as demonstrated below:
.Messages(messages => messages.AllDay(
Also it would be great if you send us back the updated resource file - we will include it in next official release of UI for ASP.NET MVC.
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