STILL about i3 & chrome & ibus

final solution

first install lxde-core, the lightest one

sudo apt install lxde-core

then u can step into lxde, just run:

startx

or

xinit

then maybe u wang to use ibus-*(for example I use ibus-rime)
u need to install some softwares like

sudo apt install ibus ibus-rime ibus-gtk ibus-gtk3 ibus-qt4 

well, u are very happy, because u can input chinese in your Linux OS
even in Chrome or Chromium-browser
But when u want to switch to one more light WM, just like ##i3-wm##
u just find that there are some unhappy issues...
when u cannot input chinese(use ibus) in your modern Broswers like Chrome, but u can use it in lxde, then u can borrow somethings frome LXDE, not just input essue.

Replace

just edit the startup file of LXDE

sudo vim `which startlxde`

just replace the last line:

# Start the LXDE session
exec /usr/bin/lxsession -s LXDE -e LXDE

to

# Start the i3 session
exec i3

bingo