I generally have a “home” Firefox window with my most used tabs pinned. Sometimes I close it before another window, so I was frustrated to “lose” it and having to redo my pins. But recently I discovered this feature. Joy!
You’re being downvoted or something but it’s same for me.
I love Firefox but every time I update it there’s this page with “Yay now you’re safe because you updated” that randomly can open as a new tab in my existing session or as a new window with a single tab and erase my previous session. And I hate it. Like, this page doesn’t give me any useful information, I never asked for it, I can’t turn it off, and that’s not all of the problem, even more, this stupid page loses my information and undoes my work of opening and arranging my tabs the way I like.
It might be true but still I don’t understand why it has to work like that and it’s not intuitive at all.