@omi-kun
I chose to use Opera believing it was more respectful of my privacy but this is now the second time all tabs disappeared in all workspaces. Fortunately, because I'd lost so much before, I created Speed Dial folders for each of my workspaces just before I triggered the update and was therefore able to bring them back.
Nonetheless this is a painful process as Opera doesn't appear to have any backup/restore mechanism (or if it does, it's very well hidden).
I'm no back on the hunt path for my next browser! What a shame - I hope someone from Opera reads this. I understand that browsers are "free", but I would gladly pay good money to have basic features.
I like the workspaces feature of Opera (although the selection of icons is dismal) as it allows me to organize my open tabs and I hope I can find something elsewhere.