You mean NX, I guess, not X2 (there's no such protocol). However: I am using NX over two chained WANs without such problems. For some time I even used it for working on machines on the other side of the Atlantic ocean - and it worked flawlessly. 

@Yan: you could try setting the connection type to ADSL or even ISDN and retry.

Uli

Bob Harold <bobh@halfgoat.com> schrieb am Do., 14. März 2019, 02:50:

On Wed, Mar 13, 2019 at 5:17 AM Ulrich Sibiller <uli42@gmx.de> wrote:
On Wed, Mar 13, 2019 at 9:10 AM Yan Zhang <kriszhyan@gmail.com> wrote:

>> > I am using Emacs 24.5.1 with x2go client version 4.1.2.0 in Windows 10. My server OS is Ubuntu 16.04 and the x2goserver comes from the PPA repo.

You could try updating your nx-libs to nightly and retry:
https://sunweavers.net/blog/node/20

> The difference is whether I start mark region (by hitting "ctrl+space") before moving cursor. The client will only stuck if I first start mark region and then hold cursor-moving keys like "ctrl+n" or "ctrl+p" for a few seconds.

Ok, understood. But still not replicable for me.

>  I tried "xev -event keyboard" in a XFCE session and did not observe any missing keystrokes.

Nor did I. So maybe this is bug in emacs. I tested with 24.3.1, can
you downgrade?

Uli

Just a thought - there is some lag in the screen updates from the remote host when using a protocol like x2.  It is possible that holding the keys for a few seconds, with auto-repeat, has buffered enough copies of the keystroke to scroll the file all the way to the end, even after you let go.  Is that possible?

-- 
Bob Harold