protonmail did the oddest thing to me the other day. It sent an email to my gmail account to inform me that I had received an email at my protonmail address. I was stunned. The main point of having the protonmail account was to keep google out of my business.
Now I have to find a provider that doesn't leak in the dumbest of ways.
The browser have to intercept 302 redirects and javascript .location assignments, open safe locations in a different container. Would that be a new window or the same window but with container change?
In the former scenario you'd basically get 2 new tabs, in the later you'd have a tab represent two different containers based on where you navigate in history.