Full screen multi window with DirectX

I’m working with Monogame DX in Windows 7 with two very similar monitors and I’m trying to make the game run fullscreen in both displays. The multi window support works ok until the creation of the secondary GameWindow, this second window does not cover the screen which is 1920x1080. Instead, the client bounds are 1920x1054 and this leaves an uncovered area at the bottom of the screen. I used the exact same code that is used in the PR #1465. Any thoughts on why this is happening?