For the Chinese input method, the input state(English or Chinese) can be
switched by the ‘shift' key on keyboard by pressing it and then releasing it
quickly(about in 200ms). It works well in all applications I tested
except Emacs.

In Emacs, if I press shift+Enter and then release it quickly(about
200ms), the state of the input method switches. This happens for the
following keys:
shift+Enter
shift+tab
shift+Backspace
shift+F[1~12]

And it doesn’t happen for ascii chars like a, b, c, d …

I talked to an author of an input method. And he guesses that Emacs
maybe processes some keyboard events and leave the keyup event of shift
to the input method. So it switches the state. This does’t happen for
other applications.

It’s on macOS 10.13.6.


In emacs with Chinese input method active,


In GNU Emacs 26.3.50 (build 1, x86_64-apple-darwin17.7.0, NS appkit-1561.61 Version 10.13.6 (Build 17G8037))
 of 2019-10-30 built on jundeMac
Repository revision: 3ee8ee8476fef2a5e8159f7597e36e0953295ce2
Windowing system distributor ‘Apple', version 10.3.1561
Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Configured using:
 ‘configure —with-ns '--enable-locallisppath=/Library/Application
 Support/Emacs/${version}/site-lisp:/Library/Application
 Support/Emacs/site-lisp’ --with-modules --disable-acl
 —without-makeinfo CFLAGS=-O2’

Configured features:
JPEG RSVG GLIB NOTIFY GNUTLS LIBXML2 ZLIB TOOLKIT_SCROLL_BARS NS MODULES
THREADS LCMS2

Important settings:
  value of $LANG: zh_CN.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  ido-everywhere: t
  display-line-numbers-mode: t
  global-hl-line-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny dired dired-loaddefs
format-spec rfc822 mml mml-sec epa derived epg gnus-util rmail
rmail-loaddefs mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util mail-prsvr mail-utils package easymenu epg-config url-handlers
url-parse auth-source cl-seq eieio eieio-core cl-macs eieio-loaddefs
password-cache url-vars windmove ido seq byte-opt gv bytecomp
byte-compile cconv cl-loaddefs cl-lib display-line-numbers hl-line
elec-pair time-date china-util tooltip eldoc electric uniquify
ediff-hook vc-hooks lisp-float-type mwheel term/ns-win ns-win
ucs-normalize mule-util term/common-win tool-bar dnd fontset image
regexp-opt fringe tabulated-list replace newcomment text-mode elisp-mode
lisp-mode prog-mode register page menu-bar rfn-eshadow isearch timer
select scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame cl-generic cham georgian utf-8-lang misc-lang
vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms cp51932
hebrew greek romanian slovak czech european ethiopic indian cyrillic
chinese composite charscript charprop case-table epa-hook jka-cmpr-hook
help simple abbrev obarray minibuffer cl-preloaded nadvice loaddefs
button faces cus-face macroexp files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote threads kqueue cocoa ns lcms2 multi-tty make-network-process
emacs)

Memory information:
((conses 16 218090 12225)
 (symbols 48 21411 2)
 (miscs 40 46 193)
 (strings 32 34279 2363)
 (string-bytes 1 920658)
 (vectors 16 37590)
 (vector-slots 8 798994 10138)
 (floats 8 56 165)
 (intervals 56 219 0)
 (buffers 992 11))