All of us that have a monitor with resolution beyond 1080p don't get a full screen picture when Full screen is selected in the options. Only a 1080p with black borders on sides and up and down. The program does not switch the resolution of our monitor to 1080p as it should.

Same problem here. I hope that this problem is addressed in a future update.

Actually, I think that the "Full Display" option should be selectable in parallel with a resolution specified by the user. Then, the display will interpolate the image if needed. This is how it usually works in most of the games.

It looks like that the current "Full Display" implementation is "Full Display Windowed" at 1920x1080.