Imagine situation like this:
You have a site with a normal link <a href="next_site.html" target="_blank"> and it just opens a new tab with site. That new site just pops up an alert immediately alert("Oh yes, that's our sweet pop up"); or with a prompt();. It prevents this site from loading, but also it somehow freezes the previous site and just starts pretty heavily using resouces (my laptop immediately gets hot). I need to close the tab. I don't know why it happens, but it happens.
To be more funny the problem does not appear when you open the site in new tab by right click or middle mouse button.
You can easily recreate it.

Just turn off that dark theme - it's really bad for now.
I don't know why they are making stuff that exist - there is a great extension for this already.
(I don't want to point any, because I don't know if I'm allowed to)

It is pretty obvious that a lot of extensions and sites uses the ALT key for some really obvious reason. But we can't use it in Opera and Opera GX, because it opens a dropdown menu .-.
It is indeed useless and annoying for me and a lot of people. Maybe just allow to delete this key bind in settings.
Also as you can deduce it after reading title and the post up to this point, that music in background is useless too. Who use it? I think all use just youtube in tab or some external app like spotify etc. It just takes space and does nothing...
But all other features are quite cool also the UI, that's why I'm still here. But don't make me switch to google chrome .-.
Wow, you read it all! Thank you
Have a nice day