INDEPENDENTLY close Firefox (Standard) windows separate from Private windows

I am looking to be able to INDEPENDENTLY close Firefox (Standard) windows separate from those running in a Private session. ATM, it does not seem possible to close just one type of Firefox session without the other. I see this possibly as a simple about:config switch which would allow one to close ALL Standard or Private windows with the respective system tray icon's "Close (All) Windows" OR the Menu's Exit selection. No other behaviors need change. USE CASE: I frequently use both types of windows and will sometimes close Firefox Standard and unintentionally loose tabs I have not saved in Private.