Several private windows share the cookies. Try logging into a website in a private window and open that website in another private window and you will be logged in.

Which is a significant flaw in the way incognito windows work with Chrome. If you have a minimized or hidden incognito window, opening a new one beats the purpose of incognito windows…

At the least, you could imagine having a shared session for all the tabs in a same window. But a new incognito window should be clear of any history.

In Chrome. Not in Safari.

Waoh. Never knew this. I would happily switch to safari, if only it has those amazing extensions that I have in my chrome.

What about separate Chrome profiles?

Not quite the same in that saved history, password, etc are in separate profiles. Also, you can have tabs from different containers in a same window.

I don't think so: I'm currently logged in on HN. When I open a new private window, I'm logged in as well.

This is really annoying when you always use your web browser in private mode, but don't close it regularly. It means that e.g. youtube already builds a profile about me from my previous searches even though I'm not logged in. If I were that concerned I would close Firefox, but the usability issue is just too big for me. Having the best of both worls would be awesome.

> When I open a new private window, I'm logged in as well.

Not in firefox, or, at least not for me.

It depends on whether all private windows have been closed. If you open a new private window when another is already open, you remain logged into sites. If you close all your private windows and then open another, it's a clean slate. (At least for me.)

I can see why they do this but it is actually not what I expected. I'd expect all windows to have their own set of cookies and credentials and for all tabs associated with a window to share them.

Are you logged in in a private window? I use the setting "Always use private browsing mode" in FF52, so all of my windows are in private mode, but whenever I open a new (private) window, I'm still logged in. I suspect you'd get the same behaviour with the default settings, and opening two new private windows.

FF53 on Ubuntu, stock settings.

And yes, you're right if I log in on either one of two private windows then the other one is also logged in. That's actually a bug in FF afaic.

FWIW, Chrome has the ability to do multi-user. So I have different users for different accounts. I know that's not perfect but it does more or less force me to close and reopen. PITA but worth having nearly defined browser silos.

And in a VPN and I think you get at least some chance at some privacy. Hopefully.

I use QupZilla, a random Chrome-based browser because it starts a new session for every new window (not tab).

Even Internet Explorer has File > New Session.

Not exactly. I've a "work" container that retains my work-related sessions (on gmail, issue tracker, etc). So if I come back yesterday, I open a work container and I'm back to work.

Meanwhile, my personal container won't log me with my gmail/work account when I watch cat videos on youtube.

If I used facebook, I'd have a facebook-specific container. Just open a tab in it, and I'm logged in, but no cross-container tracking.

Also, history is retained, and all in one big pool (unlike having actual separate profiles).

Your browser (FF and Chrome, at least) only has a single private session, regardless of whether you have multiple windows in private mode or not.