very dangerous, crash and bring mozilla useless. delete the file in appdata for save your tab if this appen.

I must say that I am truely disappointed; I spent over 10 minutes to figure out how it works, and I haven't got it to work. All I wanted is to organize my opened tabs in folders, and I just couldn't figure out how to do that. Very disappointing.

This add-on seriously needs a manual. The author probably thinks it's completely intuitive, but I have no idea how to use it. Just about everything I try has a different effect than I expected.

I do not have the interface that is promised by the screen copies. Neither folders, nor organize. Only Opened tabs, and saved tabs. And under that, a tree view with the current folder, and when I click on it the other ones in the lower level. Why ?
I can do nothing of that, so I have to uninstall it.
I do not know what happened that I did not have the extension as it is supposed to be.

Lost around a thousand tabs and I don't know which.
When searching for a keyword to close tabs, as soon as I close a tab the list gets reloaded with other contet. So if I click on several close symbols in a row, tabzen will replace the list I am working with and put a category with all my tabs directly under the mousepointer, closing this category closes all tabs. Closing hundreds of tabs stalled Firefox and it restarted. The tabs already closed was thus no longer to be found in the "recently closed tabs" list.

Putting a button that means "throw all your stuff away" right under the mouse pointer while I am clicking it isn't a nice feature. It's nothing but deliberate and vicious.

All I can say is HUH? This addon doesn't seem to me to add any value at all to FF that isn't already there to begin with. It's nothing more than a way to bookmark tabs and a few other bells and whistles that are also already there. I see no point to this whatsoever. Rather use Tree Style Tabs which works on the fly.

You say :
“USAGE : Access the popup menu by clicking on the Tabzen logo on the toolbar, to the right of the address bar. The menu lists the open tabs and windows.”
Instead of the list of all tabs, only the current tab appears.
I have to click on the gear wheel on top right to see all open tabs and folders I created.
When I created a first folder "VPN ", all tabs ended up in it.
I had to move these tabs to the root, but some are duplicated.
In short, I'm waiting for this extension to be ready before reinstalling it.

Very confusing UI.

I have a major and a minor complaint about this add-on.
The major one is that I just lost my 250+ tabs, and have only been able to remember enough about them to get about 50 back. I used the hot key to save all tabs, deleted the save as I was going to add and remove a few tabs, only to find that the hot key CLOSES ALL OF THE TABS AS IT SAVES THEM. The fact that the tabs are going to be closed is NOT MENTIONED ANYWHERE IN THE INSTRUCTIONS. Why does it close them all?!?!
The minor complaint is that if you save all the tabs from all of the windows and then load them, it loads them all into one window rather than opening a window for each set.
It seems like it would be a useful extension except that it closed tabs without warning. I'm incredibly annoyed about that. For that alone I'd give it negative stars if possible.

We can't manage tab because context menu "create folder" doesn't create a folder but URL ...

Installed on android. Does nothing at all on android! Clearly another add-on that is not compatible and is untested. Annoying! This site shouldn't even allow android Firefox to install addons when it isn't compatible and yet here we are, the site is an absolute mess and reflection of the piss poor state Mozilla is currently in. Pathetic.