Yes, that's the one I want fixing, and possibly moving from extension to feature.
Why would you create a privacy tool, and then not offer it in private mode. Makes no sense.
(You can setup Firefox so it's permanently in Private Mode and clears history and data on exit - as per Libre comment above -,which is how I have it set)
> disposable containers which isolate the data websites store (cookies, storage, and more) from each other
Granted, they're not in private broswing mode just normal mode, but same effect
[0] https://addons.mozilla.org/en-US/firefox/addon/temporary-con...