Capturing Keyboard input during fullscreen game app while running unity app in background

My question is the following.
I would like to build a small prog to capture movements of a game (Not in Unity).
I built a small prog which draws line when I press the movement buttons. The unity prog runs in background and captures Keyboard Inputs just fine (so even if I use the keyboard in other programs, unity app still draws the lines), but when I run another full screen game app, then it stops working.
Does anyone have any suggestion?
I am using the “UnityRawInput” library.
Thanks

Did you ever get this working?