An absolute must have. This is a game changer.

The single most important usability addon Ive ever encountered! I am quite stoked that Firefox will bring Treestyles to the native Browser.

I encountered some quirks with the Addon sometimes, like after closing hundreds of Tabs that the "x" button of a tab doesnt work any longer and you got to restart the browser,
or the quirk that if you restore a previous session due to accidently closing the window, that all the temporary container tabs are sitting ducks without the tmp-container wrapped around them - the tabs than need to be relaunched in a new created tab that hosts a tmp-container.
But despite that, I never lost any tab or anything!
Great addon - and my goto on every machine since ever!
With some usercss you can even get rid of the tab-bar, which is great to save vertical space and make use of wasted pixels for website content!

I still prefer Sideberry over the native Firefox "Vertical Tab" feature: It takes less space, allows for grouping, better shows grouped tabs, allows for colors, and actually has so many settings that you will be overwhelmed at first!

Many thanks!

Tab-Gruppen können nicht einfach gewechselt werden, somit ist es für mich nur eine Tab weitere Tab-Ansicht

it's sooooo simple but good

This is not first time that after closing and opening the browser, all tabs are lost. Very unstable add-on. Not suitable for work.

Ce n'est pas dans ma langue

Must have extension! So many options.