It would be great if the editor could detect, when I am about to add a duplicate citation.
I just tested it this way and it showed me no warning:
- Add an URL via automatic tool (tab) there.
- Go somewhere else and add another URL, paste exactly the same URL as before.
- And it created exactly the same text and did not notify me, one was there already.
I think checking whether one is about to re-add exactly the same URL would be an easy check, you can add.