Solved Lower resolutions make smaller screens on my laptop

This occurs especially during games, my native resolution is 1366x768 but whenever I choose a
lower resolution than that in games, the size of the game on the screen becomes smaller than my
laptop's display/screen (15.6"). Why does this happen? Is it a laptop issue only? My older laptop had the same problem.
Is there a way to fix this?

PS: I have the latest graphics drivers.

Thx in advance!

Ok, solved!! The solution was simple, all I had to do was go into my Intel graphics settings and set it to scale Full Screen instead of 16:9. Now all my games are in full screen regardless of their resolutions.