Expected Behavior

On terminal display:
baba端子lalaを搭載

BackSpace press one time，expect

 baba端子lalaを搭<cursor position should be here>

Actual Behavior

baba端子lalaを搭<a unwanted SPACE is here><the cursor position is here, not correct.>

Additional Comments

BackSpace only delete only a half part of multi-bytes word, it was regarded as two separate char. The cursor position is not correct.