This topic (here and in other threads) has been around for years now.
Opera people, your browser is amazing, but if I needed to point at a place of improvement I'd say improving full screen is the single most important one.
Having to switch back to windowed mode to bring up the address bar defies the point of full screen navigation. Also I need to escape form input fields and exiting with the esc key is far too sensitive and makes the whole thing very annoying.
Lastly, getting the mouse near the top should get you the address bar, not the full screen message.
A nice-to-have addition would also be a command menu in the Sublime Text editor fashion.
I created an account with you just to let you know my thoughts on this.