Impossible to "Edit single file" to edit an empty file?

Hello,

According to this doc about the web editor, there is a “single file edit” that exists when the file is not empty.

However, it is not possible to use that “single file edit” feature to edit an empty file.

Am I missing something ? Is there a setting allowing that feature to be used on an empty file ?
Or something preventing it ?

Thanks in advance for any answer.

For the readers, I created an issue about it :

Bug has been identified and will be fixed on a future version of Gitlab.
This thread is now closed.