I was going to suggest this myself. I just discovered, to my dismay, that *any* of my addresses can be used for login! I had designated one additional address to be "public facing" so that I could share that address freely on the web, without revealing the username for *all* my ProtonMail services... Turns out that is not how things work.
Enable/disable would be an excellent addition. Given a choice, I would only use my original username for login - and that's it.
I was going to suggest this myself. I just discovered, to my dismay, that *any* of my addresses can be used for login! I had designated one additional address to be "public facing" so that I could share that address freely on the web, without revealing the username for *all* my ProtonMail services... Turns out that is not how things work.
Enable/disable would be an excellent addition. Given a choice, I would only use my original username for login - and that's it.