Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature currently requires accessing the site using the built-in Safari browser.
That's odd,I don't remember pressing it.This isn't a bug, more like a not very obvious feature.
Above the text field look for 3 dots.
When you press them, a few buttons will appear, one of them looks like [ ]
Press it, and the text editor will be enabled.
It's to switch between text editor and code editor.