EDIT: DON'T INSTALL TAB SESSION MANAGER.

Kroppy, thank you very much for the tip. After removing TAB SESSION MANAGER, your extension now works perfectly. Maybe adding that information to the description and/or work with the owner of that extension to make both compatible.

This is the most wonderful extension for Firefox, period.

First impressions: I'm just now testing Tree Tabs, as a long-time Tree Style Tab user who's followed Tree Tabs from the first Vivaldi forum posts. It has some very nice features out of the box. I love the groups, unloading, and session backups, as well as the auto-correcting tab order for keyboard shortcuts.
Additional thoughts: So far, pretty awesome. Literally replaces three extensions, and very nearly three more, at least. Groups, tree-hierarchical tabs, and tab search are fully replaced, and it almost replaces a session manager, tab-unload manager, and an undo-close menu.
If wishes were... : It'd be helpful to have the session feature save automatically every x minutes and allow selection of a session to load. Tab-unloading would be more useful if it could be automated on a timed basis with a whitelist. Undo-close would be nifty if it had a list of the last few closed tabs, but it works fine as-is.

Bugs: None found yet?
Noteworthy: The audio icon only appears on that specific tab, even if it is within a collapsed tree. This can be a bother if more than one tree or branch of possibly-guilty tabs exists. It might be better to display the icon on the nearest visible parent tab, if the playing tab is hidden, as well as on the group title, to aid in locating an offending tab, especially in cases of sneaky, ill-behaved ads, but also for those who (over)(ab)use YouTube and the like.
Edit: Found the sidebar unresponsive at times. The problem was predictably resolved when I disabled my session manager and a tab-unloading addon. Seems that many (most?) things that interact with tabs directly may interfere with Tree Tabs.

I use this as a replacement for the discarded panorama feature. Tree structure proves to be handy or even extremely useful. A spot-on use of the lateral panel, making for a perfect integration.

Still sketchy in nightly (currently 61) with new windows popping up when dragging tabs. Otherwise, quite stable and reliable. [Edit] As of Nightly 61, no tab dragging issues after several hours testing in 61. So I was wrong, nothing sketdchy about it :). Awesome!

I would still browse pre-quantum if it wasn't for this. THanks indeed.

Seems to break the lateral panel or rather lock it down. I installed an experimental feature (notes) which uses the side panel as well. NO dice. I suppose it's worth looking into it here :
https://testpilot.firefox.com/experiments

Basically a great addition. But the order of the tabs in Tree Tabs vs. what Firefox thinks the order to be is completely off. If you close a tab you never know where you will land next. In the preferences you can set that the next tab should be the one above/below, but this does not work reliably.
I make heavy use of the "group" feature and more often than not the tab I land is an a totally different group.

This extension makes me say "WOW!" It has so much functions to control tens and hundreds of tabs.. Definetely more fucntional than Tree Style Tabs plugin which I used before, I going to use this plugin instead.

Спасибо за последнее обновление! Стало работать гораздо лучше и удобнее.

Однако появился новый баг. Точно описать его пока не могу. Суть в том, что актуальная родительская вкладка может переместиться в предстоящую родительскую при открытии дочерней и так-же переместиться обратно при просмотре дочерней. Сам до конца еще не разобрался

Thank you for your efforts in manufacturing this software, it's useful and beautiful. I have already recommended this software to my friend. I have only two questions, both of them are about the session.

(1)When I restart the Firefox, and click "History -> Restore previous history" in Firefox menu, tabs come back but without folders and groups, I have to import my previous session backup to solve this problem, using the "Import and merge session" option.I hope this is an automatic operation.

(2)When I start the Firefox, click the add-on's menu "Import session", and select my session backup, and horrible things have appeared, Firefox start loading the tab one by one, because amount of my tabs is huge(about 150), so it cost me 20 mins to load, and finally used 7G memory.

Can you solve these 2 problems? My Firefox's version is "Firefox Quantum 58.0.2(64-bit)". Looking forward to your reply! Thank you!

It is the most excellent tree type tab I know.

but i have suggestion.

Mistakes occur in the order of the tabs when using for a long time.
If it is difficult to suppress the occurrence of a mistake, I want a button to synchronize the order of the visible tabs and the order of the tabs recognized by the FF.

Make Tree Style Tabs looks overrated. =)

Hey, a suggestion:
What about a new config to bind groups to containers?
Then opening a new tab on that group will always open a tab of the chosen container.

After each restart the sidebar appears blank. Resetting to defaults brings it back, but again only until next browser restart. Otherwise very good experience.

Suggestions:
- reverse order option (new tabs at top)
- double click closes tab (if it's even possible in quantum)
- fogging long text instead of triple dot (looks better and cleaner)
- option to completely hide icons bar (search, settings, etc.)

This is fantastic! The features are so much better than Tree Style Tab! Why doesn't this appear as a related extension or higher in the search rankings!?

Very good extension!

Can you add Color Tabs Group? Like in Tab Kit?
Color tabs based on their parent: tabs that are related and are part of the same group have the same color

And can you add Unread/Active/Pending Tabs Color/Style too! :)
Thanks! :)

This addons very comfort use as "dynamic bookmarks" and I have a few good recommendation for improvement:
- folders must always collapsed default or make this setting for it. Folders good using as subgroups for left tabs groups;
- when actived tab located in folder, all tabs operation related with creating new tab (such as clone of tab in folder, new tab) must work only in current folder. -- New tabs creating in current folder;
- with close folder all inner tabs and subfolders must closing;
- add possibility unload all tabs for folders (in folder content menu);
- add possibility open all tabs in folder in new left tab group with deleting this folder;
- for economy memory your tabs must to makings (html code) during activating left tab group or during unfold folders/trees;
- real FF tabs must creating and linking only after activate your tabs;
- option unload tabs must close real FF tabs, but your tabs must markeds like unloads and stay in list.

Also all your tabs you can save in special folder of FF bookmarks and working from this place, where subdirs first level = groups for tab in left... Option for set base bookmark dir for addon can add to addon config.

If in FF enabled option about save tabs before close program, then with restoring tabs of browser, you addon just must merge self ungrouped tabs with other.

PS Addon is full replacement FF tabs, which must hide. Meanwhile I hide it through "userChrome.css".

Great extension, thank you.

The main issue I have is when restoring a session (using a different extension), all the group and folder layouts are gone.

I use Tab Session Manager to manage my session as it automatically backs up the session every X minutes + on window close which is essential for my needs. Tree Tabs cannot do this except for manually exporting sessions which is inconvenient in daily use.

Perhaps there is a way to "play nice" with TSM, such as TT automatically saving a history of the group and folder layouts so when restoring my session with TSM, TT can re-group and re-folder what it remembers? The alternative would be to compete with what TSM already does very well and save sessions (I assume sessions also save group/folder layouts) every X minutes and on window close, thus replacing TSM in my case. For me, I prefer to use one group and split it using folders.

The other issue that I've noticed is that when moving a tab to a folder using TT after a TSM session restore, my pinned tabs had their order rearranged. I don't know if other tabs we also rearranged. Who's to blame, I don't know, but I thought to mention it anyway.

Lastly, I'd like to see a "Automatically collapse other trees on expand" option but for folders.

Thank you once again for a fine extension.

I like it so far. Long-time user of Tree Style Tabs and only tried this one because TST now doesn't *replace* the normal tabs, it just adds the vertical ones to the side, leaving the originals in place. Turns out this one does too. Don't see the purpose of adding the vertical tabs if the horizontals can't be removed.

Somewhat disappointed.

I am going to second almost everything "Anonymous user 762ab4" said down below, at least all the compliments. Unlike that user, though, I still recommend and keep using this extension, since I don't seem to have the same instability issues regarding opening Firefox. I only witnessed a single little glitch at launch, that I will include in my list of improvement suggestions (which incidently also include all of "user 762ab4"'s own suggestions :-)):

- So, most times I open Firefox, although I get my session back (including groups and tree structure), my own theme (that I, of course, saved) very rarely loads up automatically. It is an easy fix, since I simply have to open the Tree Tabs option page, which gets my theme to instantly load up. It's not a big deal, but it certainly isn't the intended behaviour, and it still adds a step to the process of getting the browser up and ready and to my liking...

- Like several other users already mentioned, I have also experienced the issue of tab dragging between groups actually opening them in a new window, and it is indeed quite annoying.

- Although I do save my sessions very regularly, an auto-backup function would be wonderful.

- I also support the suggestion of integrating Tree Tabs with Firefox sync. I definitely would have a great use for this possibility.

- The Tree Tabs integrated right-click "Undo close" doesn't seem to be working (but Firefox "Undo close tab" functionality, when you right-click on the horizontal tab bar, does.)

- I don't know if this can be done, but, if it can, I would love for Tree Tabs to systematically integrate all available right-click functionalities (that is, include all the functionalities from other installed extensions.)

- Like many other commenters suggested, it would be wonderful to see some indication of the container a tab was opened in, if any. Getting an option to directly be able to chose to open a new tab in a container would also be very useful.
*** BUT, unlike what another reviewer suggested - which Kroppy then said he "had in plans", which really worried me - I would absolutely HATE to see containers used in place of the groups! Contrary to what said reviewer claimed, there is no "redundancy" there. Containers and groups of tabs have very distinct purposes (I won't elaborate on the distinction, there's tons of info on that topic). I for one know how to use both properly, and certainly do, which is why I need to be able to make the most of both functionalities. Several extensions already base their so-called "groups" on containers, and they don't do the trick for me. Seeing Tree Tabs join this trend would unfortunately be a total deal-breaker, as far as I'm concerned.

- Regarding the theme customization (which is already amazing, I must say!):
1. I would kind of like to be able to change the font, yes, but what I would REALLY love would be to change the size of the font of the names of the groups (those that lay vertically, and that we click on to access each group's tabs). I really have trouble reading them, and being able to increase their size slightly would help a lot.
2. Just like user 762ab4 mentioned, it would be great if the theme customization was extended so we could choose to visually distinguish between folders and their respective tabs.
3. Maybe some more details could be added at some places, in the customization options, since it's not always obvious what each option button applies to. For instance, in the "Toolbar" section, the buttons in the grouping of 4 apply to the Search sub-menu, but unless this sub-menu happens to be open at the time you are doing the customization, you have no idea what you are modifying.

- Finally, I'd like to say that I am definitely against "Anonymous user eb4478"'s suggestion (sorry, user! :-)) of only loading one group at a time. Here again, several extensions already do that, and that is another of the main reasons I use Tree Tabs, and would never use any of those other extensions again.


In conclusion, Kroppy, this is a powerful, incredibly helpful and very unique extension, and I thank you for all the time and effort you are dedicating to this project! Thank you, thank you, thank you! :-)

Great addon. Much better than Tree Style Tabs in many aspects. Give it a try and you won't regret it.

I have been looking for a replacement for Tab Groups and this is promising.

However, I have a lot of pages that I refer to, my hope is that someday the developer(s) will add the functionality to open one group at a time so that I don't have to load all them into memory at once. Ideally I would like to start Firefox with no open group then have the ability of opening a group and when shifting to another group all of the tabs I had open would save and close and the chosen group open all tabs. In other words each group of tabs could be loaded separately.

Please fix the tabs dragging from group to group. Sometimes it works normal, but more often I got a tab in separate window.
It's very annoying.

Sad to say that Tree Tabs is less buggy than Piro's "Tree Style Tab."

Although a few navigation bugs make Tree Tabs awkward to use,

1) When the option "Append child tabs to the top" is enabled, Ctrl+Tab|Ctrl+Shift+Tab navigation browses tabs as if "Append child tabs to the bottom" was enabled -- in reverse order.
c.f. Open two tabs from parent, Ctrl+Tab once, the bottom (2nd tab is activated). Ctrl+Tab again, the focus moves UPWARDS (not down) to the first child tab.Ctrl+Tab a third time, focus leaves the tree downwards to the next parent tab.
Expected Behaviour, Ctrl+Tab: 1st child activated, then second child, then leaving tree to next parent tab.

2) When navigating tabs via Ctrl+Tab|Ctrl+Shift+Tab, collapsed trees are expanded and traversed, instead of skipping to the next parent tab.

- Existing unloaded tabs are ignored when saving Tree Tabs session.

- No option to change Tree Tabs font family (perhaps can be rectified with CSS like pre-Firefox 57).

Faster than Tree Style Tabs. But it's necessary to do something with synchronization with tabbrowser-tabs. Moving tabs in tabbrowser-tabs is not tracked.