@seanandrei you have to uninstall chrome, and when you start the installation of the extension, will ask you if you want to install it on opera browser... that's the only way. And after that you might reinstall Chrome. I don't use Chrome - don't like it. It's working on all systems (windows 11 and the last mac OS)

@rwhite777 you can use a chrome extension. Here it is: https://chrome.google.com/webstore/detail/dont-close-window-with-la/dlnpfhfhmkiebpnlllpehlmklgdggbhn?hl=en
Just install it on opera and you're done. Is working on mac opera as well.