but a set of e-mail lists was created without being asked, and e-mail seems to have landed there 🙂 The show also under the uppermost boxes, '' unread" etc.
That's normal. Opera automatically detects list headers in messages, creates Mailing list views for each list. In "All Messages/Unread" (or any other view), you can click the "settings for this view" icon on the toolbar above the message list, goto "show" and uncheck "show mailing lists".
I have about 30 subfolders
IMAP subfolders? If so, that should work just fine.
if there are no way to import account settings and folder structure, I think I will have to wit untilm I have more time experimenting.
Thanks. May I ask what's the differences?
It's really easier if you just download and try it. You mightn't miss anything, or you might miss an obscure little checkbox option I would not be able to tell because making a table with every feature/option in Opera 12.x would be totally time consuming and not worth it. There are new features like Stash, some signature features (Speed Dial, Off-road/Turbo, etc) and other small ones were already developed into the new browser, while others are under development (e.g. sync), some work differently, lack a characteristic or changed places (the Recently Closed trash can menu is in the main menu now, some settings in other places, etc) and others we know that won't come back (or don't know whether will come back someday or not).
You may be interested in a comparison I made in this topic on Opera 20 vs. Chrome so you can see benefits that the new version still has over it and other browsers (of course it's not a complete list and may not represent fully the latest version available at the time you read it).
I may have discovered what was causing this. I use Ghostery to block a lot of ads and things of that nature, a few of which I unblocked for testing a website. I blocked these again and the box seems to be gone for good... hopefully.