Using HX Stomp, there are black boxes touching some shortcuts. Also when we are selecting category in the effects list, and we touch the fs1 or fs2 sensor, we got a black box on the screen, and covers a part of the display. Also when you enter in the tuner option and you touch fs1 and fs2 sensors, you got a question 'swap fs1 and fs2' and with any option you select, this pop up stay there mixing with the tuner screen