Editing file fails if a a different calendar is chosen

<img width="923" alt="image" src="https://user-images.githubusercontent.com/9727812/226112499-5387cfaf-1bf6-4d51-8f03-26defcec825b.png">

<img width="351" alt="image" src="https://user-images.githubusercontent.com/9727812/226112512-75c6631e-84a0-4131-9203-98d944e96404.png">

This tag will be added to the file:
```
<default-calendar-type>ISO8601</default-calendar-type>
```