Dual screen resolution

Hi, I’ve got a problem:
I currently have 2 screens, the resolution of both is the same (1680 x 1050)
I set the player in the interface for Unity resolution (1680x2) and 1050.
And finally I have one large window that is displayed on two screens except it lacks a few centimeters on each side and at the top and bottom of the window to cover the entire screen.
In fact it seems that the resolution that I impose the Unity player is not quite the same as the screen resolution.
I also tried detecting the resolution automatically (screen.width) and the result is the same.
Someone could maybe help me ?

Nobody to help me please ?

There’s a Screen.width and Screen.height if that helps?

I saw reference to it here Unity - Manual: IMGUI Basics