I like this add-on

Indispensable. Have scores of tabs open that you just want to get back to later? One click sends them all to OneTab and closes all those open tabs that are eating up your system's memory. Lots of features and ease of use make this a winner. Plus, it was very easy to move all my tabs over to FireFox when I walked away from Chrome.

Works as intended with one very annoying "feature", whenever you open your browser the one tab page auto loads after a delay of few seconds and steals the focus from whichever tab you were previously on. So if you open your browser to quickly go to website or to google something quick, while you are typing in the address bar suddenly you get switched to the One Tab page. I would prefer if there was a option in the settings to disable this so that you can open the one tab page only when you want.

The worst add-on I had on my system for months. Had the same running in Chrome, where it works quite well. On Firefox (72.01, 64 bit) win7 64 pro, it let me lose more than 250 tabs collected over a long time. Hope to retrieve them in my backups, but this add-on should be taken of the list immediately. One star is still one too many.
If the developers want to keep a small fraction of credibility, they should publish a method how to retrieve the lost tabs yet today.