QGroundControl / Rover can't move backwards

I have rover based on RPI4 + Navio2 + xbox360 gamepad/joystick. In manual mode I can control rover to move forward and turn sideways. Joystick middle is zero throttle, but I can’t make rover to move backwards. I know it worked earlier with Mission Planner, but I can’t find relevant setting in QGC.
Is it QGC config problem or is issue somewhere else?