Custom GS Window size? 1920x1080

[FPS_NEWMAN]

When I try to change the GS Window to the custom ratio of 1920x1080 it keeps reverting to 1904x1032. I don't know why and would like some help. My monitor resolution is 1920x1080.

[FPS_NEWMAN]

If I want it that size should I just select fit to window/screen?

[Eloris]

Just double-click the window to go fullscreen. The fit to window/screen determines whether the game image will be stretched or kept at it's original aspect ratio of either 4:3 or 16:9, with black bars as filler.

[nosisab Ken Keleh]

make sure you have write access to the configuration files, the symptom is that of PCSX2 installed at C:\Program Files...

It that's so the recommendation is uninstalling the emulator and installing somewhere else, something like C:\Emulators should do the trick.
this simple procedure could solve the actual problem and spare you from more on near future.