SO it places All tabs to a Side Window List. Too Bad doesn't Separate which tabs are in different window. IT SHOWS ALL TABS IN THE SIDE BAR.

Can't see the list of Closed Tabs &　can't Remove the Close TAB button from accidental select.

It works more stable than tree tab viewers.
But for several thousand tabs there is a few seconds delay even for several recent tabs.
Also, for sidebar mouse wheel minimum move scrolls several pages instead of only one page.

Like others, I was not impressed with the pop-up alert, which had more of an intrusive viral affront effect. One star demotion for that.

I am disappointed that the developer has chosen to discontinue this useful app that has been available to those who supported him for many years and came to rely on its features. Even sadder is that the decision is based on incomplete information and incorrect assumptions. As many have already stated, there are too many 2FA apps to mention that do not require personal information.

I have used several apps for various sites that only require an install, and always opted for 2FA apps that do not require personal information, including a phone number, or supplied mini al useless data. When a confirmation email is required, I use a throwaway address, now also available with Firefox Relay.

Since being confronted with this notice, I have been in search of alternative tab helper apps, so would welcome posts about any recommend replacement.

A smart range of features, however I prefer extensions that are broadly compatible with multi-window use of Firefox.

https://github.com/Drive4ik/simple-tab-groups/issues/759#issuecomment-787096598

ATH V1.2.18 (updated to 1 Jun 20)
FF V77 and 77.0.1 (updated to 4 Jun 20)
1. Since these FF updates ATH displays a blank panel, ie. it is not registering there are tabs open
2. Additionally, ATH Settings have been reset (size, theme, etc.)
Prior to these FF updates ATH was working fine. Other Add-ons are also not displaying properly since these FF updates. Another great job from Mozilla!!
ATH would be 5-star if it had a badge showing number of tabs open.

The instructions are baffling, and need to be rewritten more simply. But the addon does the main thing I want. It provides a list of all the tabs in all the browser windows.

Let me save you some time. Go to:
Tools menu > Addons > Extensions > All Tabs Helper > Options > Appearance section.

There you can increase the "BrowserAction popup width" with the arrow to a maximum of 600 pixels. This is the width of the popup list that shows up when clicking the addon icon. This makes the list wider and more easily scannable. If you click in the form, you can type in an even larger width up to 800 pixels before the list width maxes out on my monitors: 2560x1440 and 1920x1080.

In the "Multi-window" section check the box for "Enable multi-window mode".
Also, in that section check the box for "List host windows tab first".

Those 2 changes put all tabs from all browser windows in the list. It puts the tabs from the current window at the top.

Pretty good, very useful for managing tabs. Only problem is the scrolling is a little buggy when my mouse is directly over the list. If my mouse is on the scroll bar it's fine.

It was saving my ass every day as I use to have open more than 250 pages. But last 14 days it stop to work, showing only empty list :-(

It works great BUT...

https://support.mozilla.org/en-US/kb/permission-request-messages-firefox-extensions#w_access-your-data-for-all-websites

The extension can read the content of any web page you visit as well as data you enter into those web pages, such as usernames and passwords.

EDIT:
Thank you very much for the reply.
That permission is scary, and for good reason.
I am not able to understand the source code, which would require much time on every update, anyway.
Without that permission, it would be perfect.
Even if that should require to remove some features.
Anyway, you made an open source addon which works great.
And you read the feedback.
Therefore I give you my compliments and raise the score to four stars.
I am sorry for myself, because I won't be using such a useful addon.
Thank you very much for your work :)

Font-size is tiny by default and cannot be increased. Please provide an option for increasing the size so we may be able to read the tab list better.

The addon has been very useful. The only problem at the moment is that the sidebar shortcut is not working (CTRL+SHIFT+9).

I've been using this add-on for years and mostly it's such a time-saver & productivity boost, kudos to the developers, but! This add-on SERIOUSLY LACKS SHORTCUT KEYS! There is absolutely no way to do the simplest use-case of 1) access the tab list (then) 2. search for desired tab (then) 3. switch to one-of-the found tab(s) (done) without touching the mouse. FF's built-in search tab feature (start typing in the location bar with '% ') is now my goto mouseless-switch-tab-solution.

- When opening it for the first time, the current tab is not visible and is not selected in tab list until you manually switch to another tab.
- dark theme isn't activated when Windows theme is changed to dark theme. (as Firefox automatically changes its theme to match Windows theme).
- When moving mouse over a tab in tab list it would be nice to show that tab's full title on a tooltip message in case sidebar width is small that only part of tab title is visible.

I would like the option to reload selected tabs

I like it although I find the horizontal space too tight and the hit-target for the close icon is too small. Can you make the horizontal spacing match the built-in "List all tabs" dropdown in Firefox? Also can you make the close icon a bit bigger? Alternatively, you could make that an option so you don't upset existing users.

Can you add an option for [tab switching by mouse wheel scrolling] ?
Another plugins such as [Tree tabs] [Tree Style Tab] all have this option and it makes tab switchings much easier. Wish this addon also has that feature.

Same problem here ATH-button 1.1.12 freezes FF 56.0.2esr completely.

I can understand that it's not possible to maintain backward compatibility with all older FF versions, but it would be great to make an exception for the last FFesr compatible with non-webext extentions (actually 56.0.2esr).

Where can I find version 1.1.7 (version mentionned by mmmel4real as working) ? Which ATH-settings might be generating the issue ?

EDIT: I did some tests. The last version with a correctly working button is 1.0.58. From 1.1.1 on there are those problems (for 1.1.12 : Script: chrome://aios/content/aios_old.js:26)

I love this addon.
Only one problem, all of a sudden when I right click on a tab, there is an entry in the menu that opens from ATH right on the bottom of the list. Very annoying because normally that bottom one is for clicking to close the tab.
Can that be changed in some way.

This has quickly become one of my must-have addons, I tend to not close tabs and the "switch to" feature of the AwesomeBar only works when it wants to, so I end up opening multiple of the same page. The ability to easily spot duplicate tabs, and also closing tabs more efficiently were what I looked for when I found this addon.

There seems to be a bug with the addon though. I can't find a way to save settings, there is no save button except for the one for CSS, and when I close the settings and open them back up, the changes are not saved.

Great add-on. I just wish there were a few more standard tab control items in the sidebar context menu. Like: close tabs left/right (above/below), bookmark selected, reopen in container, etc.

Good, but IMO the search box should take focus inmediatelly after activate it. That would make the addon more usable.

Great addon do you plan to make it easier to notice the current active tab on the tab list?. Now the font is bold but is hard to notice anyway. Could you change the color for the text or add like a symbol or something at the beginning to make it more noticeable?