The second release candidate for WordPress 5.4 is available now. The release is still targeted for March 31st.
Riad Benguella announced that fullscreen mode will be activated by default in the visual editor starting with this release:
“Note that for now, that’s a local setting, which is why it’s going to reset when your preferences do, including incognito mode. Future releases will store the setting in the WordPress database.”
This late change generated a lot of questions and pushback, especially after Matt Mullenweg took responsibility for it as his decision. 🗯️
Personally, I found the experience to be jarring after my site auto-updated to the latest beta release. I might get used to it, but I right now I feel something is missing in fullscreen mode, and it wouldn’t be my default choice.