@gravitytale it's possible using the sitebar site panel flag. The only downside is that it isn't groupped with the other sidebar apps, but rather below the bookmarks, pinboards, etc. icons.
@burnout426 Thanks. Yes, I guess that's it…security. It's there in Safari. It just makes it painful to fill out credit card information when buying something over the web.
@hosseintest1 I suppose I'm just +1-ing this. Over the many months I've used Opera, I keep wanting to work out how to split a tab island into two separate tab islands, and I haven't worked out how to do it. The tab islands are a great idea, but it's either not well developed yet, or not intuitive.