Best extension ever hands down.

NOTE THIS EDIT: I just noticed configuring TST and following it's advice of changing configuratin 'browser.tabs.multiselect' to true, but it didn't exist! This is 77.0.1 64-bit Linux version and that option didn't exists - I added it, but as it was not there to begin with, I doubt it will be of any help that I added it... Advice?
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Awesome! I used to love an old legacy add-on called Tab Mix Plus, which really is an awesome add-on for the tab bar, but now I love the tab tree much more - it's also specifically nice with small netbooks, like my Acer Aspire One D270 (old, I know, but still works marvels if not put under too heavy strain), that have a widescreen display and very low vertical resolution - you can hide the sidebar if you need to, although most of the time it's not a problem, and you save the height of the tab bar in vertical resolution available to show the actual page. With such small displays it really does matter a lot.

Edit: Many people are complaining about the lack of search function. I'm not sure what exactly they mean, I'm completely satisfied with being able to search tabs using the location bar - you can enable this from FireFox settings. However maybe a search function that only shows the matching tabs (and the tab-tree they are part of) in the sidebar - when it's empty it would show them all. I can't think of another way they mean, but I'm really fully content with searching for the tab using location bar anyway :)

give an option to save those whole taps list in a group.so that one can reopen those tabs when ever neccessery

Billant just very helpful.

Decent customization, the large lacking feature is the ability to hide all of your tabs up top.

The main reason I still haven't switched to Chrome

cool addon

This should be the default way of managing tabs for any desktop web browser. A must-have plugin.

Works well enough, but breaks in Nightly 74