Add a Fullscreen Button on the Title Bar in Windows 10
Some other Windows 10 software have a fullscreen button to the left of the minimize button. I think it would be pretty nice to have that button in opera.
Look at this picture for an example:
I'm running Opera 41 on Win 10 right now. Upper right are 3 standard window buttons, Minimize, Full Screen and Close. Can you attach a screen shot of your opera window?