@leocg You've obviously missed my point. Yes, I know all about those options. However, not all browsers choose to open every tab, but for the top one in each window, upon relaunching, thus saving many Gigs of RAM, and allowing the user to decide if and when to open any of those tabs. So my question is why doesn't Opera go this time & energy-saving route, instead of the pointless one of having to open every single one?
Opera for Mac