How can I fix it?

To
2

When i was just going to play minecraft and clicked play, the game was very very small. Then wanted to press f11 to make it as big as my screen again. It got bigger, but not as big as the screen and moved to the upper right corner. Then hit f11 again and the game returned to its previous size. In the settings, I noticed that I was in full screen. When I turned on the full screen, it just got a little bigger and shifted back into the right corner. I turned off the full screen again and the game became very small again. Then I pressed the rectangle, which either minimized or enlarged the game / program. This worked, but I had an edge at the top and bottom (the task bar at the bottom) that didn't go away. Now my question is how can I fix this? So that I have again full screen that is the size of my screen and has no border?
I thank you in advance. Lg

pi

Optifine should be able to fix that, if not, just restart. Until 1.12 there was a bug that if you had full screen active and deactivated it again, you can no longer scale the program

Optifine has also fixed this

To

Ok all right