The complaint in the article is legit, and it sounds completely plausible that is it due to re-write to React, as avoiding rendering of off-screen content is fa

The complaint in the article is legit, and it sounds completely plausible that is it due to re-write to React, as avoiding rendering of off-screen content is fairly standard practice in React, as a performance optimization. But that really is about the management of the re-write, not the tech. Someone at github decided to not render off-screen content. That breaks expectations compared to how it worked before, and that is why it feels like the app is going downhill. The bigger point being that if anyone is doing a re-write, and trying to match the existing UX... that needs to be a deeper match than just getting the pixels in the right place.