Thank you!

Works!
Would be nice to be able to sync the tab groups among multiple devices.

Perfect replacement for Firefox's group tabs feature they had back in version 45.

You are god.

отлично!!! возвращает управление группами вкладок

OMG, tab groups are back in town. Hey, listen. Really. You are doing Firefox great. Thanks a lot! :'D

Ay, dios, tab groups ha vuelto. Ey, escucha. En serio. Estás haciendo Firefox grande. Gracias de corazón.

This add on is very close to how the original Firefox Tab Groups (Panorama) was. The one major feature it's missing is the lack of a "create new Group" option in the "Send To Group" tab context menu item. Currently the send to group context menu item only shows already existing groups and a option to refresh groups, if the Dev adds the "create new group" function then along with Firefox's new multi tab group selecting, we could shift select multiple tabs and then right click and create a new tab group out of them instantly.

Doing perfectly its job! Thumbs up @projectdelphai!

Sorry, The application works slowly, especially when switching between tabs and Panorama Tab Groups. This poor performance is since the fresh installation of this extension. It should be definitely improved.
I use FF Quantum 65.0.1 (64-bit) Portable version.

Useful, intuitive and stable ! Keep up the good work !