So, when I play test my game (made with RPG Maker MV), the full screen resizes and occupies almost the whole screen (besides the letter-boxed black bars at each side), but when I try to enable full screen in my browser hosted game, it's what happens.

Is there any way to fix that? Is this something related to the engine itself or it's a problem from Itch.io side?

If you want to check it first hand to see on your own browser, here's the link to the project:

https://cleanwaterdev.itch.io/learnrpgmakermv

Thanks in advance!