So, this appears to promise automatic and manual resolution - perfect! Reality? You have to fight against this as soon as you don't do what it wants.

The most hilarious part is the manual deduplication. As the other person below notes, the "close all" button really closes all - it does NOT deduplicate your open tabs. That is to say, for 4 duplicated tabs, you get 0, not 1. So, not deduplication. It really is "close all", not "resolve all". In most cases you don't want to press it, ever.

If you want to resolve manually... Well, you get only a tiny bit of space for the list of all duplicates. You have to unpin the settings and collapse, exactly what you thought. Oh, did you think opening the settings in a tab will help, because it will scroll unlike the tiny popup, so you'd get a long list? Nope! Well, then, you finally collapse the settings, clicking left and right. And finally you can see it well - a list of tab names with [x], you click the [x], and... nothing happens! That's right, you have to refresh the whole settings tab to see the list updated. And did you think the list will be the same? Nooo, it is sorted, so as soon as you close one dupe and refresh, the list is in completely different order.

So, what did I expect? Lots more space for the duplicate list. Also, updating it in real time as you close the tabs, so I could just click over on the first item and as it closes, more shuffle back into the position, and of course when the last one remains, it is not a dupe anymore so it goes off the list. I also expected the close all button to do that dance for me.

As to the automatic resolution, that is also a bit weird. When you open all links in new tabs, then it probably works. But if you click a link to open in the current tab and it suddenly disappears, that's not exactly what I expected.

I'm really disappointed. But it does not even look like there are other addons that could do the job instead.

Hours gone to waste because of this piece of crap. Instead of closing just duplicates, it closed all tabs that I had 2 or more of open. So for example, I had two copies of a tab. It closed them both. Ctrl-shift-T only goes back so far. I'm going to have to start all the way back at the beginning now. I can't even express my rage at this useless extension. I completely regret I ever got it.

It's super great but I have an issue now on Linux Firefox 91. Duplicate Tabs requires Containers, that I deactivate. Containers, when activated for Duplicate Tabs, hinder my right-click, C keyboard shortcut to quickly copy URL of a link, which I need every 5 minutes. I had to deactivate this extension, sadly...

This is exactly what I want!

Request: I want a switch to temporarily disable this from toolbar.

I seriously can't believe this isn't part of those other tab management plugins.

Please optimize this extension for Firefox Android

It doesn't work well recently. It needs to be fixed.

This Extension is nearly perfect! The best of the duplicate tab closing extensions on Firefox. I would love to see a couple features that I think would push this into the perfect 5* range.

[1] Whitelist should be available with the 'do nothing' option so that it applies to the "Close All" button as well, so that I can exclude certain pages (such as New Tab or about:blank) but still use that option.
[2] Add the option to pop up a Notification on duplicate. Automatically removing tabs has caused me issues, so I do not use that feature, but I still would love an option to know when I am duplicating an existing tab in the moment.
[3] In the duplicate tab notification window it would be nice to have the options to close New or Old duplicated tab, or to do nothing.

Thanks for all the hard work!