I tried since yesterday all the buttoms Shift+ctrl+z and backspace nothing ,I have tried all keys available and doesn't do anything ,Do you push Shift+ctrl+z release and then backspace or + /-??
the problem seems to be that this is a USB keyboard and may not accept too many keys at the same time ,so I assing instead Cntrl+shift+Z , I assing M and then I assing a letter to increase selection and decrease selection wich used to be assing it by + and - I assing