I sent this mail 10 hours ago. But I didn’t see it on http://lists.gnu.org/archive/html/emacs-devel/2019-01/index.html.

So I resent it with another mail provider.

At 2019-01-20 20:26:08, "Eli Zaretskii" <eliz@gnu.org> wrote:
>
>In that bug report you talk about "shaking".  Did you mean flickering?  Because I don't think I see any shaking in the clip.
>
>In any case, this input method is not from Emacs, right?  So I couldn't try reproducing the problem on my machine.

Yes, it should be flickering. The same content is cleared(at the same time, the cursor goes to the beginning of the content area) 
and then redisplayed(and the cursor comes back) during inputing.

Yes, the input method is not from emacs. It is provided by the OS.

That bug only happens on macOS. And other apps(including macVim) on the OS don’t have same problem. So it must be a bug of emacs.