Multiple Windows, Single Session od losnappas

I DO recommend closing your MAIN window LAST. Especially so, if you're using something like Tree Style Tabs.

What it does
Basically, you close a window with the X and this addon will restart that window when Firefox reboots. If you want to permanently close a window, then use the addon button.

Update:
Turns out pressing Ctrl+Q or closing from the menu does this (and works better).

It's written in purescript, which is honestly pretty terrible for this.(hindsight)

Contribs welcome:
https://gitlab.com/losnappas/multiple-windows-single-session