I discovered "something" so i wanted to share it, in case somebody may find it useful someday!
I've a game that can be toogle between full screen and windowed. I actually don't have a full screen, it's a borderless screen made to fit the whole screen.
Anyway, when the game begins i have that full screen mode activated, and when changing to windowed and back to fullscreen, the windows bar always appeared on top and didn't seem there was a way to hide it again.
But trying, i found that if i specify the position of the window is 0,0, the bar can't be seen. Something like this:
Window.Position = new Point(0, 0);
bla bla bla
Don't know why but anyway, hope it can save some time and a headache to somebody!