I have shared a computer with people, but we definitely don't want our stuff open at the same time. I would find that confusing and a bit of a violation of privacy. So that leaves me (and most people I assume) just trying to imagine what it is that you are not happy with. And I honestly don't know what you are talking about when you say 'regular shortcut'. As far as I know, there is only one kind of shortcut in windows. It's a icon that runs a command of your choice, with an icon of your choice, placed in a location of your choice (any folder, any part of the start menu, or somewhere on the taskbar). So when you talk about shortcuts not being the regular one, I don't know what you mean.
But look, if you say it's bad for your use-case - I believe you. When I said that it was a stretch to blame Firefox, I didn't mean it was a non-issue. What I had in mind was that your primary complaint seems to be about what Windows is doing rather than what Firefox is doing. In any case, like I said before: if it isn't doing what you need then it makes sense to look elsewhere. Good luck to you.