Yeah, this problem is bugging the heck out of me.

@tamikonatsu Nope. Nothing since the last time I checked a couple weeks ago. I recently switched back to Vivaldi, though, so it could have changed in the last couple weeks. This issue is one of the reasons I switched, plus the fact that Bitwarden doesn't work with Opera on my Android, and I absolutely need it to work with my default browser, so I couldn't sync between my Opera desktop and whatever android browser I was using. Now that Vivaldi has workspaces (instead of just the tab groups which didn't offer enough simple separation between groups), I'm happy to use it again.

@synthercat Yes! This is happening to me too! I don't have a picture showing up there for me, so I can't even tell if I'm signed out until I click the icon.

Yeah, this problem is bugging the heck out of me.

I had both Macs running with Opera running on both of them. If I don't Sign out and re-sign in to set up sync, the button won't show up. I've seen this reply on other related posts, but it's baloney. The other browsers don't need to be running currently, they just need to have synced their tabs.

I have the Opera browser set up on 2 Mac machines and 1 Windows machine and I have sync all set up on each of them so I can easily share open tabs. On my Mac machines, if I Quit the browser, the Tabs sidebar item is gone when I start it back up again and it doesn't show up at all as an option to be added to the sidebar. If I then Sign Out of sync and then sign back in and tell it to sync, the sidebar button comes back (so does the icon near the top right that indicates I'm signed in, which also disappears after quitting).

The Tabs sidebar icon is also missing from my Windows machine, but I haven't tried anything to bring it back yet.