Suggestions:

• Customizable light/dark mode (and/or text/background colors)

• Option to remove the "Restore All Tabs" option entirely

• The amount of items to show in the list should be capped at whatever the maximum Sessions value is; at the time of writing this review, it's 25, but if there's a way to have it at the variable itself so that it follows it automatically without the author needing to update it manually, that would be perfect

• The amount of items to show in the list should maybe be 25 by default (or, rather, whatever the maximum sessions variable is, in any given Firefox version)

• Add a (removable) option to forget all listed tabs

• Allow holding the shift or control keys (or command key on Mac) to select multiple tabs from the list

• When right-clicking (a) tab(s) in the list, there should be an option to forget the tab(s)

• If possible, add functionality for recently-closed windows.
– Maybe listed tabs could be grouped by window.
– Upon right-clicking a tab, these options could be displayed in a context menu:
— "Open in Current Window"
— "Open in New Window"
— "Open in New Private Window"
— If the tab's window is currently closed (otherwise this option should be grayed-out): "Reopen Closed Window & Tab(s)"
– Maybe a listed recently-closed window could be right-clicked on to reopen all of its tabs, or left-clicked on to toggle collapsing it in the list.

this is the simple closed history button, i wish it could follow the color themes for the background

BEST Add-on Click on the Icon and shows you the LIST of CLOSED Tabs History.

Funziona bene, ma l'altra estensione Undo Last Tab Button ha le stesse funzioni ed è più completa

"Maximum width of the button's menu" option please like your 'Undo Close Tab Button'.

Does not show any list of closed tabs, only "Restore All Tabs".

While this addon actually works - it has some problem with its settings. Changing number of tabs to show in the list to anything more than 25 will cease addon of showing anything at all.
Also, keep in mind, that this setting doesn't override internal Firefox config `browser.sessionstore.max_tabs_undo` which is 10 by default. So, unless you modify the latter, the former won't show you more than 10.
Also, internal pages don't show icons in this addons' list, like Options (about:preferences), Addons (about:addons), other add-on's pages and etc.
And, lastly, FYI, Recently Closed Tabs is a native Firefox feature. You can find it under Library -> History -> Recently Closed Tabs. Library is a bookshelf-like icon on your FF toolbar. There's also Recently Closed Windows there.

Very good addon and thanks to the developer.

This works GREAT! Thanks!

Perfect. This is what I want.

It was working fine for a while, then it stopped. Now when I click on it there are no tabs. It stopped working almost a week ago.

Sorry - doesn't show any opened-then-closed tab for re-opening.
I tried several ...
Not a single one.
If it would be possible, I'd give zero stars.

Works fine with FF ver 61.

Doesn't work.

It doesn't work, plain and simple. Maybe it has before recent FF updates. You click on it, and the list of closed tabs stays empty

Exacly what I was looking for (like in vivaldi / opera)

Just Perfect

Shows all 20 of my past tabs for this FF session. Quick, safe, easy to read. Thanks. I use several of Button Guy's buttons