still an issue in 1.10.2 in linux by using gcin.
There are no fix in linux by using gcin, and no other third party solution now.
currently I just could use copy and paste to type chinese in the chat.
this bug will effect linux too.
for now, i did not find a way to solve it.
this problem is only occur in minecraft 1.6.X
I found the IM in linux is force close in C code
the code in src/native/linux/org_lwjgl_opengl_LinuxKeyboard.c:87
set @im=none will cause the IM complete not working in linux
remove this code will re-enable the IM connect.