Overwrite the whole document content of inherited language variants

[turbo-ele]

When i create an inherited language variant, i am expecting that all contents of the original document are always reflected in this document.
This behavior though can be overwritten by

• clicking on the header of a content block and
• click on overwrite,
  which in my opinion is a little questionable, as it's not clear to the user, that the whole document is overwritten instead of just the block and all the full document inheritance is destroyed by this action.
  Because after that, if i add a new block to the original document, it is not being added to the inherited document anymore.

So my questions are:

1. Is this behavior intended?
2. Is it somehow possible to see if a document is fully inherited, or just single blocks in the admin-ui? The only possibility i found so far is to check in the database, if content is set for the specific document in the documents_editables table.
3. Can it be undone? Except by deleting the content element in the database?