Firefox

I have been playing around with pwa-like experiences, and as part of that I tested "kiosk mode".

For those who don't know, you can start a "kiosk window" with the command firefox -kiosk --new-window <url>, which will open that url in fullscreen without a titlebar, right click menu, any overlays like the link preview or loading text, ...
I cancelled the fullscreen flag of my window, and had a resizable fully functional website in a frameless window.

Which was great and all, until I realized that in my running profile now every newly opened window is also in kiosk mode, and right click was globally disabled. My running firefox instance has been infected by the kiosk disease.

Anyway, it's not a large issue, I can just restart my infected instance. But I hate restarting my browser, it usually runs for multiple months.

My question is, is it possible to leave kiosk mode without restarting firefox?