OK, pretty simple, don’t be put off by all the stuff in the console window.
- In your regular profile go to the Basic HTML Gmail tab and press the following keys together. Ctrl-Shift-I (that is the letter I not number 1).
- A section will open up, usually at the bottom of the page. It is used by developers to debug but you don’t have to concern yourself with any of it, just let it sit there. The tab that you’re viewing - Gmail - will be resized and be a bit smaller, it might look like the page is on a mobile phone. Don’t worry about that either.
- On the GMail page use the mouse to click the “standard” link and let the page refresh.
- That’s all I did and everything went back to normal. You can close the console by pressing Ctrl-Shift-I again or clicking the “X” at the top left of the console menu.