Input Manager - prevent keyboard keys mapping to Xbox controller buttons

Hi,
I am working on the game which should be controlled with keyboard as well with a joystick. I am testing the game with my Xbox 360 controller and I defined one axis like this:
111481-mapping.png

Now I am able to fill the FireBeam axis with space on keyboard and also with A button on my controller, but the problem is that space is also mapped on B controller button by default. The result is that I can fire with both A and B buttons, which is something I don´t really want (B button will have another functionality later).

Is there some easy way to prevent default keyboard-controller mapping, or should I figure out more advanced solution through scripting? Thanks for your answers!

Ok, so I´ve found the answer - the problem was with Steam client running in the background - if you are running Steam and your controller is connected to the PC, it maps kontroller keys to keyboard keys by default - my problem was caused by this, haha.

After switching the Steam off, everything is ok