I've been having the same issue on my Mac. Sometimes Cmd+W closes just a tab, and sometimes it closes the entire set of tabs in a window. It's an annoying bug, but at least I finally figured out that under the History menu, there's a Reopen Last Closed Window command as a way to deal with it for now...
Do more on the web, with a fast and secure browser!
Download Opera browser with:
- built-in ad blocker
- battery saver
- free VPN