A nice addon to replace original Tab Groups.
But there are two majors problems :
1. At startup, Simple Tab Groups always reopen 2 or 3 tabs that where closed in previous session
2. It's no more possible to switch groups of tab after a few minutes of usage. There is an error "Invalid tab ID". Only possible way is to restart firefox or reload STG addon.
Note : I have near 300 tabs opened in 11 groups (75 in groups with most tabs), if this help

Update 13.02.2019
It look like version 3.3.7 fixed problems described above.
I have no more closed tabs auto re-opening and since update I don't have Invalid Tab ID error.
Or maybe it's Firefox 65 ? Anyway, 5 stars now !

it just works.
it help managing multiple tabs and doing it pretty neat

Thanks for great addon.
I have question,
is there any way to change backup folder?

thanks for the fix ! it's good again

First of all: A BIG THANK YOU! This is looking very good! FF after 56 was a big regression!
Tab groups should be part(optionally or not) of every FF, like tabs are. I mean if you have files, you have to have folders/directories!
In order to be 100% helpful, tabs, have to have 4 important things:
1. Free arrange and rename the tab groups;
2. Saving the session at will and automatically(every hour or so) before FF crashes or is closed normally;
3. Possibility to move tabs from one group to another.
4. A "tab group bar" above the tab bar, with a button to hide/show the "tab group bar".
I guess you have already covered most of this and I hope you will do your best for the others!
Cheers !

EDIT : take a look at this: https://postimg.cc/SJhgfGdn
for clarification about paragraph 4. See that green T to the right of the tab bar....that is the button with which left click show/hide the "tab group bar".

Panorama is back... and better! Hooray

Cool

Thanks so much for essentially reviving the Tab Groups/Panorama feature! Some other extensions have tried and not quite hit the mark, but this one is the best so far. Hope you're able to take it even further as the WebExtensions API expands!

Thank you for reincarnating such a vital feature. Last thing I miss( and miss SO much) is 'free arrange' - I mean to have the tabs on the whole screen, not in a small pre-arranged window. may I ask when it will be ready? I really cant stay on old Firefox no more(

I think you just changed the way I will use Firefox. This is absolutely ideal.

I wonder if you have distant plans to implement the ability to change the window background/theme. It would be a luxury, I know; but I feel compelled to nudge you in that direction anyway. ;)

good addon.
please enhance the performance in groups change.

Best FF addon! Thank you!

This has a lot of potential to become the best tab grouping addon for Firefox. Design should be more elegant in Dark Mode as well. Thanks to the developer, you did a great job!

Works like a charm and is very snappy. Thanks for all the effort!