Excellent usability BUT frequently consumes ~95% of CPU, therefore I can't recommend this add-on

Found out why OneTab wasn't working entirely by accident. Still disappointed by the lack of response from the devs. If anyone else has an issue with OneTab not loading, though, try this:

"I'd changed 2 settings in about:config

image.webp.enabled was set to false (default true)
image.http.accept was set to "*/*" where the default was "image/webp,*/*" - all without the quotes"

I found this for a seemingly unrelated problem with YouTube thumbnails not loading, but sure enough it also corrected my OneTab issue. No idea how the settings were changed in the first place.

Perfect! Does exactly what it's designed to do without a lot of redundant functions that other addons already perform. I use this in tandem with Session Buddy and Tab Wrangler to keep a reign on FF memory usage. This is an excellent feature in addition to them. It's function, quite simply, is to close all tabs (not pinned if you choose), and create a simple list of them all to be easily retrieved. YES, it opens it's own tab for this purpose. So what? One is better than a hundred. Saw that ridiculous complaint in one review. Don't listen to all the one star reviews. Almost all of them have no clue how addons work or their intended purpose. This does precisely what it's supposed to. Period.

It's so useful. Sometimes I'll be searching things and I open too many tabs. When I need to clean them up again, this helps me organize my tabs so much easier.