This does not seem like a b2evo problem.

What's the real problem? That Firefox does not delete your cookies, when you ask him to do so? How are you telling Firefox to delete them?!

thanks for your reply.

I ask Firefox to delete all cookies each time I close it.

But some cookies stay on Firefox after restarting, like google and b2evolution.

So I just only want to know how it is possible ? What sort of cookie is used by b2evolution to stay even if I close Firefox.

Can you reproduce it on the demo site? (demo.b2evolution.net)

How do you tell Firefox to delete all cookies? Maybe you only tell it to delete session cookies? Is it an extension that you're using?

I have not the same on demo.b2evo site.

When I log to my b2evolution account, a cookie is created name : cookieb2evosession

When I close firefox, all existing cookies are deleted. Excepted some of them, like cookie from google or my b2evolution site.

So I just want to know how it is possible and what is the code for that cookie ! ;)

I hope you understand me !

The end of cookie is the end of session of firefox (because it is what i ask to firefox). The normal end of cookie is year 2017

It's "just a normal" cookie, but no session cookie by itself. Maybe the FF code to delete it on close is buggy.
Sorry, I don't have another idea.