I'm a professional and power user (now 4K+ tabs opened).
I'm using Sidebery since 2020: with lateral tabs, grouping and panels, Sidebery changed my way of using the browser and it's great, organized and efficient.
Thank you so much!
P.s. Probably it's the main reason because I stay with Firefox.

Suggestion: in the years, it happened 2 or 3 times that it has lost the hierarchy of my tabs and flattened the list, so I've set Sidebery appropriate automatic snapshots and to avoid eventual bugs, if a version works without problems, I update Sidebery to a new release only after many weeks since it has been released.

Best tab organizer I've seen (and I've been on the 'Net since Netscape!)

Quite good but not as nice looking as Zen browser's

The best sidebar there is.
Thanks a lot!

Fantastic plugin. I eventually used my profile's userChrome.css to hide Firefox's horizontal tab row because I just don't use it anymore, and I much prefer Sidebery's use of tab panels over Floorp's use of workspaces (not to mention Sidebery + Firefox don't crash on me constantly, or ever).

Of note: if/when customizing the size of tabs height in Sidebery's style settings, stick to px and don't use relative units like ems, as this will mess up your drag & drop interactions.

Tabs started to merge, needs fixing ASAP

Tab panels have started to merge. This is very bad. Now dozens of sorted tabs are mixed together. The extension is broken. UPDATE IT.

WOW! Very in-depth and extremely customizable tab extension, clearly a lot of effort has gone into it's development. Thanks to the dev(s)!

It started out ok but several times now I start Firefox and all my groups are empty, and instead, all tabs are just listed in one window, hundreds of them! what a complete waste of time. I spent hours fixing it only to find several days later it had done it again. I did some searching and found this is quite an old bug and seems to be has never really been resolved. Stay away from this extension if you value your links

This add-on is honestly amazing! It takes a bit of work setting everything up but that is only because it is so insanely costumisable.

Awesome add-on! This helps me a lot for managing multiple projects at the same time. I feel it could use a few more colors and icons for distinguishing projects, but since it's free, it's still definitely 5 stars from me.