Thanks for the links but they didn't help me. I have various custom filters from Adguard and probably they would have to be somehow converted to work in Opera. Unfortunately, as also stated in the link to another thread on Opera forum, there are no information, instructions or whatsoever how to do it. Opera should compile a manual!
"There is virtually no documentation about this anywhere. Not even in the release notes! It would be great if a manual for the general syntax is specified online somewhere for advanced users. Users who are unaware might just port their ABP custom filters, hoping that they would work. An online conversion facility to transform filters in other syntax to Opera syntax would also be useful."
Have no other choice than to run my custom filters in Adguard. Shame.
Sure its possible, but thats not what Opera is trying to be. They are trying to make their browser different from Chrome even though they share code. While they aren't there yet the browser is yet young. They aren't trying to be just a slightly different clone of Chrome. That means maintaining compatibility with Chrome extensions and apps, especially with their much smaller dev team, would not be possible. Thats why some extensions don't work.
You can change the icon used for the speed dial by opening the webpage who's icon you wish to change and clicking the heart menu to the right of the address bar. From there you can use the arrow buttons on that popup to cycle through a selection of icons. A thumbnail of the entire webpage will always be one of the selections you can make.
Just a note, it is not a live preview like in Opera 12. So it wont change as time goes on.
OK, I have found a solution ... you have to download the standalone application (Music Manager) to your PC through which you can upload and then play music on Google Play interface in Opera.
The problem in Opera is that while it supports Chrome extensions, it doesn't support Chrome applications. That's the problem. Therefore you have to use the Music Manager.
I hope that Opera will come up soon with support of Chrome applications!