Allow Editors to choose whether to replicate all translations or only default language

Yeah, agreed, the validation stuff seems a bit complicated for what it brings. The label field is prefilled, someone would need to go through the trouble of removing the content and then not duplicate the translations. I'm fine with just removing that and the test coverage for it.

We've been using this for a while and it works quote well, there's a confusing issue with paragraphs though, their translations don't get deleted when deleting a translation. So when you then re-add a translation. But I think that's an issue with ERR/paragraphs and happens when manually removing a translation as well.

#3249609: Replicate in a different user interface language from the original language of the Entity will cause error on a multilingual site → is also related and does the untranslated change always, which probably makes sense?

We went the opposite direction with this issue: our checkbox says replicate only $default_language. It felt more natural.

Also, if we were to add an event called ReplicateUiOnlyUntranslatedEvent then paragraphs ReplicateFieldSubscriber could catch it and remove the translations from paragraphs.

https://gist.github.com/chx/ec7a6f1ec990016c218d6c0cf5a1372e

Let me know how to proceed: if there's any interest at all I will submit the paragraphs part in the relevant issue queue (and commit the relevant bricks patch too) and I will add the event to the current patch. Further let me know whether there's interest in swapping the direction in the current patch.

Forgot about your comment, we did actually run in the paragraphs issue again and created 🐛 When a translated node is duplicated with no translation, the paragraphs are still translated Active , I don't think a separate event is necessary.