We can't write Japanese exactly on chat, commandblock and sign

minecraft 1.2.7, 1.2.8, 1.2.9 and 1.2.10 has input bug on chat!
when I write Japanese on chat, commandblock and sign "こんにちは", the chat was inputted
"ｋここｎこんこんｎこんにこんにｃこんにｃｈこんにちこんにちｈこんにちは"
we can't write Japanese on chat and commandblock.
this bug occurs windows10 only.
please fix this bug!