How do you paste a saved passsword?
With Opera 12, the login/password area is highlighted so that you know there is a saved password available. Then you just do ctl-enter to paste the login/password.
I looked thru all of the Vivaldi keyboard shortcuts and could not find how to paste the login information. How is it done?
There is no shortcut. If you focus the login field, hit Cursor ↓ and a login (list if more than one per page) will be shown.