Picture above is emacs 26.2, it is ok. I can't figure out why emacs 26.3 and 27.0.50 are not ok with the same config of emacs 26.2. Maybe I should trye to compile emacs from source. I use emacs on linux by compiling from trunk. But I don't set up develop environment on windows. 

------------------ 原始邮件 ------------------
发件人:&nbsp;"Juanma Barranquero"<lekktu@gmail.com&gt;;
发送时间:&nbsp;2019年9月25日(星期三) 晚上11:22
收件人:&nbsp;"Eli Zaretskii"<eliz@gnu.org&gt;;
抄送:&nbsp;"Albert"<georgealbert@qq.com&gt;;"37495"<37495@debbugs.gnu.org&gt;;
主题:&nbsp;Re: bug#37495: 27.0.50; lwindow doesn't pass to system





On Wed, Sep 25, 2019 at 5:14 PM Eli Zaretskii <eliz@gnu.org&gt; wrote:

&gt; I see the same, FWIW, and the *Help* window pops up before I hit 'r',
&gt; just after I hit lwindow.
&gt;
&gt; I think this is normal.


Yes, it is normal. But it's not what happens to Albert.

So I think you're right, something in his system's set up is messing with keyboard handling, and it's not an Emacs thing.

But somehow it didn't affect 26.2... Weird.