On macOS, Firefox does not remember its full screen state when exiting and relaunching the application. Here's what happens:
1. Place the app in full screen by clicking the green button in the upper left of the window "Enter Full Screen".
2. Exit Firefox.
3. Launch Firefox, and it opens up with a large window but not full screen.
The problem is that the relaunch should open full screen again, just like other macOS apps do. This is annoying and has been outstanding for a long time.
