I also use Workspaces in Vivaldi, and was looking for a way to replicate the experience as best as possible. This tab manager is helping immensely with that.

No complaints. The only "issue" I have has nothing to do with the extension, but with my force of habit.

It's taking me some time to get used to the idea that here I am dealing with tabs grouped not in a single window, but MULTIPLE ones. On Vivaldi all tab groups reside on a single window. I've lost the count of times I've had to use the browser's History to restore the window I've just closed, thinking that I was shutting down the browser. :-)