I was playing a game called 'Rocket League', but when I doubleclicked the top, the top bar showing the name of the window & the bottom window bar appeared, and now the game doesn't fully fit my screen anymore. Before I did that, it would just fit perfectly in my screen & I would have to exit the game by ctrl, alt + delete or pressing the windows button. I didn't see anything but the game, not even the name above the game.
Now, I see this:
The problem is that I can't see the full game anymore.
How do I fix this?