I have just downloaded Opera with the intention to use it to play the game NanoFerma (https://nanoferma.draugas.lt/index.cfm). However, NanoFerma has its own button for 'fullscreen' that just opens up the game part of it and gives a larger window to access all areas of the game. Whenever I click on it, I just get the game headings at the top and a white screen. I have tried using 'Fullscreen' in the View menu but that works on the whole browser and not just on the game part, so does not help at all.
macOS 10.13.6 (17G65)