How can I force Opera to save the email address on https://login.microsoftonline.com ?

That login page appears extremely resilient against password saving (and consequently extremely resilient against me using it - I refuse to insert my email address every goddam single time). In Firefox I managed to save the email address so it was presented as an auto-fill option on double-clicking the email-address field.

I don't see any "wand" icon anywhere, right clicking doesn't offer me a way to store password, there's no options in the menu, and the "Password Manager" doesn't allow me to add a new entry. I tried some 5 or 6 "add-ons" but half of them just want to send my passwords online to their servers and none of them worked.

I'm using the latest version of Opera - 42.0.#.