Desktop flashing when maximizing window on second screen with Windows client

[Hybrid512]

With the Windows X2Goclient, in a multihead setup, if you maximize a windowed desktop session (MATE session for instance but I guess it happens with any DE) this window keeps on flashing and most of the time, it can't seem to get a fixed size and position.
The only workaround in that case is to resize the window by hand and not maximize it.

This doesn't seem to happen with the pre-3.6 ("x2go stable") libs but only with Arctica ones.

[nkrepo]

I have a similar issue with screen Flickering and Ubuntu mate.
It happens almost all the time while the window is maximized.
It happens for about 1 second every time the window is resized.

If the mouse is moved over the top-left corner after the client window is resized (no clicking) the flickering continues for a few more seconds.

Setup details are:
Client
Windows 10 build 1709 (Fall creators update)
x2go client 4.1.1.1 with Arctica nx-libs

Server
Ubuntu MATE 16.04 LTS

libx2go-log-perl       4.1.0.0-0~1517~ubuntu16.04.1
libx2go-server-db-perl 4.1.0.0-0~1517~ubuntu16.04.1
libx2go-server-perl    4.1.0.0-0~1517~ubuntu16.04.1
x2goagent              2:3.5.0.33-0~710~ubuntu16.04.1
x2gomatebindings       0.0.1.5-0~203~ubuntu16.04.1
x2goserver             4.1.0.0-0~1517~ubuntu16.04.1
x2goserver-common      4.1.0.0-0~1517~ubuntu16.04.1
x2goserver-extensions  4.1.0.0-0~1517~ubuntu16.04.1
x2goserver-fmbindings  4.1.0.0-0~1517~ubuntu16.04.1
x2goserver-printing    4.1.0.0-0~1517~ubuntu16.04.1
x2goserver-x2goagent   4.1.0.0-0~1517~ubuntu16.04.1
x2goserver-xsession    4.1.0.0-0~1517~ubuntu16.04.1
libnx-x11-6:amd64      2:3.5.99.14-0~816~ubuntu16.04.1
nx-x11-common          2:3.5.99.14-0~816~ubuntu16.04.1
nxagent                2:3.5.99.14-0~816~ubuntu16.04.1

I have uploaded a youtube video demonstrating the issue when the client window is maximized
Maximized client window flickering.

session.log:

NXAGENT - Version 3.5.99.14

Copyright (c) 2001, 2011 NoMachine (http://www.nomachine.com)
Copyright (c) 2008-2014 Oleksandr Shneyder <o.shneyder@phoca-gmbh.de>
Copyright (c) 2011-2016 Mike Gabriel <mike.gabriel@das-netzwerkteam.de>
Copyright (c) 2014-2016 Ulrich Sibiller <uli42@gmx.de>
Copyright (c) 2014-2016 Mihai Moldovan <ionic@ionic.de>
Copyright (c) 2015-2016 Qindel Group (http://www.qindel.com)
See https://github.com/ArcticaProject/nx-libs for more information.

Info: Agent running with pid '18606'.
Session: Starting session at 'Tue Mar  6 09:42:43 2018'.
Info: Proxy running in client mode with pid '18606'.
Info: Using errors file '/tmp/.x2go-testuser/C-testuser-50-1520322162_stDMATE_dp32/session.log'.
Info: Using stats file '/tmp/.x2go-testuser/C-testuser-50-1520322162_stDMATE_dp32/C-testuser-50-1520322162_stDMATE_dp32/stats'.
Loop: WARNING! Unrecognized session type 'unix-kde-depth_32'. Assuming agent session.
Warning: Unrecognized session type 'unix-kde-depth_32'. Assuming agent session.
Info: Waiting for connection from 'localhost' on socket 'tcp:*:51297'.
Info: Accepted connection from '127.0.0.1'.
Info: Connection with remote proxy completed.
Info: Using ADSL link parameters 1408/24/1/0.
Info: Using agent parameters 5000/10/50/0/0.
Info: Using cache parameters 4/4096KB/8192KB/8192KB.
Info: Using pack method '16m-jpeg-9' with session 'unix-kde-depth_32'.
Info: Using ZLIB data compression 1/1/32.
Info: Using ZLIB stream compression 4/4.
Info: No suitable cache file found.
Info: Listening to X11 connections on display ':50'.
Info: Established X client connection.
Info: Using shared memory parameters 1/1/0/0K.
Info: Using alpha channel in render extension.
Info: Not using local device configuration changes.
Warning: Cannot read keystroke file '/home/testuser/.nx/config/keystrokes.cfg'.
Info: using keystrokes file '/etc/nxagent/keystrokes.cfg'
Warning: ignoring keystroke 'viewport_scroll_up' (already in use by 'viewport_move_up')
Warning: ignoring keystroke 'viewport_scroll_up' (already in use by 'viewport_move_up')
Warning: ignoring keystroke 'viewport_scroll_right' (already in use by 'viewport_move_right')
Warning: ignoring keystroke 'viewport_scroll_right' (already in use by 'viewport_move_right')
Warning: ignoring keystroke 'viewport_scroll_down' (already in use by 'viewport_move_down')
Warning: ignoring keystroke 'viewport_scroll_down' (already in use by 'viewport_move_down')
Current known keystrokes:
  close_session         Ctrl+Alt+t
  switch_all_screens    Ctrl+Alt+f
  fullscreen            Ctrl+Shift+Alt+f
  minimize              Ctrl+Alt+m
  defer                 Ctrl+Alt+e
  ignore                Ctrl+Alt+BackSpace
  force_synchronization Ctrl+Alt+j
  resize                Ctrl+Alt+r
  viewport_move_left    Ctrl+Shift+Alt+Left
  viewport_move_left    Ctrl+Shift+Alt+KP_Left
  viewport_move_up      Ctrl+Alt+Up
  viewport_move_up      Ctrl+Alt+KP_Up
  viewport_move_right   Ctrl+Alt+Right
  viewport_move_right   Ctrl+Alt+KP_Right
  viewport_move_down    Ctrl+Alt+Down
  viewport_move_down    Ctrl+Alt+KP_Down
  viewport_scroll_left  Ctrl+Alt+Left
  viewport_scroll_left  Ctrl+Alt+KP_Left
  reread_keystrokes     Ctrl+Alt+k
Info: keyboard file created: '/home/testuser/.x2go/C-testuser-50-1520322162_stDMATE_dp32/keyboard'
Info: Keycode conversion auto-determined as off
*** BUG ***
In pixman_region_copy: Malformed region dst
Set a breakpoint on '_pixman_log_error' to debug

*** BUG ***
In pixman_region_union: Malformed region reg1
Set a breakpoint on '_pixman_log_error' to debug

*** BUG ***
In pixman_region_union: Malformed region new_reg
Set a breakpoint on '_pixman_log_error' to debug

*** BUG ***
In pixman_region_copy: Malformed region dst
Set a breakpoint on '_pixman_log_error' to debug

*** BUG ***
In pixman_region_union: Malformed region reg1
Set a breakpoint on '_pixman_log_error' to debug

*** BUG ***
In pixman_region_union: Malformed region new_reg
Set a breakpoint on '_pixman_log_error' to debug

*** BUG ***
In pixman_region_copy: Malformed region dst
Set a breakpoint on '_pixman_log_error' to debug

*** BUG ***
In pixman_region_intersect: Malformed region new_reg
Set a breakpoint on '_pixman_log_error' to debug

Session: Session started at 'Tue Mar  6 09:42:52 2018'.
*** BUG ***
In pixman_region_intersect: Malformed region new_reg
Set a breakpoint on '_pixman_log_error' to debug

*** BUG ***
In pixman_region_copy: Malformed region dst
Set a breakpoint on '_pixman_log_error' to debug

Info: Screen [0] resized to geometry [784x561] fullscreen [0].
Info: Screen [0] resized to geometry [1138x779] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x1168] fullscreen [0].
Info: Screen [0] resized to geometry [1393x1168] fullscreen [0].
Info: Screen [0] resized to geometry [1393x1168] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1393x919] fullscreen [0].
Info: Screen [0] resized to geometry [1446x1127] fullscreen [0].
Info: Screen [0] resized to geometry [1446x1127] fullscreen [0].
Info: Screen [0] resized to geometry [1446x1127] fullscreen [0].
Info: Screen [0] resized to geometry [1446x1107] fullscreen [0].
Info: Screen [0] resized to geometry [1507x1108] fullscreen [0].
Info: Screen [0] resized to geometry [1507x1108] fullscreen [0].
Info: Screen [0] resized to geometry [1507x1108] fullscreen [0].
Info: Screen [0] resized to geometry [1507x1108] fullscreen [0].
Info: Screen [0] resized to geometry [1507x1108] fullscreen [0].
Info: Screen [0] resized to geometry [1507x1108] fullscreen [0].
Info: Screen [0] resized to geometry [1505x941] fullscreen [0].
Info: Screen [0] resized to geometry [1505x941] fullscreen [0].
Info: Screen [0] resized to geometry [1505x941] fullscreen [0].
Info: Screen [0] resized to geometry [1505x941] fullscreen [0].
Info: Screen [0] resized to geometry [1505x941] fullscreen [0].
Info: Screen [0] resized to geometry [1505x941] fullscreen [0].
Info: Screen [0] resized to geometry [1505x941] fullscreen [0].
Info: Screen [0] resized to geometry [1505x941] fullscreen [0].
Info: Screen [0] resized to geometry [1505x941] fullscreen [0].
Info: Screen [0] resized to geometry [1505x941] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1597x1009] fullscreen [0].
Info: Screen [0] resized to geometry [1466x1004] fullscreen [0].
Info: Screen [0] resized to geometry [1466x1004] fullscreen [0].
Info: Screen [0] resized to geometry [1466x1004] fullscreen [0].
Info: Screen [0] resized to geometry [1466x1004] fullscreen [0].
Info: Screen [0] resized to geometry [1466x1004] fullscreen [0].
Info: Screen [0] resized to geometry [1466x1004] fullscreen [0].
Info: Screen [0] resized to geometry [1466x1004] fullscreen [0].
Info: Screen [0] resized to geometry [1466x1004] fullscreen [0].
Info: Screen [0] resized to geometry [1466x1004] fullscreen [0].
Info: Screen [0] resized to geometry [1466x1004] fullscreen [0].
Info: Screen [0] resized to geometry [1466x1004] fullscreen [0].
Info: Screen [0] resized to geometry [1466x1004] fullscreen [0].
Info: Screen [0] resized to geometry [1466x1004] fullscreen [0].
Info: Screen [0] resized to geometry [1466x1004] fullscreen [0].
Info: Screen [0] resized to geometry [1466x1004] fullscreen [0].
Info: Screen [0] resized to geometry [1466x1004] fullscreen [0].
Info: Screen [0] resized to geometry [1466x1004] fullscreen [0].
Info: Screen [0] resized to geometry [1466x1004] fullscreen [0].
Info: Screen [0] resized to geometry [1466x1004] fullscreen [0].
Info: Screen [0] resized to geometry [1466x1004] fullscreen [0].
Info: Screen [0] resized to geometry [1466x1004] fullscreen [0].
Info: Screen [0] resized to geometry [1466x1004] fullscreen [0].
Info: Screen [0] resized to geometry [1466x1004] fullscreen [0].
Info: Screen [0] resized to geometry [1500x1013] fullscreen [0].
Info: Screen [0] resized to geometry [1500x1013] fullscreen [0].
Info: Screen [0] resized to geometry [1500x1013] fullscreen [0].
Info: Screen [0] resized to geometry [1608x1040] fullscreen [0].
Info: Screen [0] resized to geometry [1608x1040] fullscreen [0].
Info: Screen [0] resized to geometry [1397x973] fullscreen [0].
Info: Screen [0] resized to geometry [1397x973] fullscreen [0].
Info: Screen [0] resized to geometry [1397x973] fullscreen [0].
Info: Screen [0] resized to geometry [1397x973] fullscreen [0].
Info: Screen [0] resized to geometry [1397x973] fullscreen [0].
Info: Screen [0] resized to geometry [1430x995] fullscreen [0].
Info: Screen [0] resized to geometry [1478x889] fullscreen [0].
Info: Screen [0] resized to geometry [1478x889] fullscreen [0].
Info: Screen [0] resized to geometry [1478x889] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1478x889] fullscreen [0].
Info: Screen [0] resized to geometry [1478x889] fullscreen [0].
Info: Screen [0] resized to geometry [1478x889] fullscreen [0].
Info: Screen [0] resized to geometry [1478x889] fullscreen [0].
Info: Screen [0] resized to geometry [1478x889] fullscreen [0].
Info: Screen [0] resized to geometry [1478x889] fullscreen [0].

As you can see from the log every time the client window is resized multiple resize operations are performed, without actually resize the client window. When the client window is maximized it continuously tries to resize the client window to the maximized resolution of 1858x1177.

Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1858x1177] fullscreen [0].

[nkrepo]

Tested also with Centos 6.9 with Gnome 2.28.2 and the flickering can be also triggered. I am appending the session log bellow.

Setup details are:
Client
Windows 10 build 1709 (Fall creators update)
x2go client 4.1.1.1 with Arctica nx-libs

Server
Centos 5.9 with Gnome 2.28.2

perl-Capture-Tiny-0.23-0.0x2go1.el6.noarch
libXcompext3-3.5.0.33-0.0x2go1.1.git20180204.776.main.el6.x86_64
perl-X2Go-Server-4.1.0.0-0.0x2go1.1.git20180302.1517.main.el6.x86_64
perl-X2Go-Server-DB-4.1.0.0-0.0x2go1.1.git20180302.1517.main.el6.x86_64
x2goserver-extensions-4.1.0.0-0.0x2go1.1.git20180302.1517.main.el6.x86_64
perl-X2Go-Log-4.1.0.0-0.0x2go1.1.git20180302.1517.main.el6.x86_64
x2goserver-4.1.0.0-0.0x2go1.1.git20180302.1517.main.el6.x86_64
x2goserver-x2goagent-4.1.0.0-0.0x2go1.1.git20180302.1517.main.el6.x86_64
x2goserver-xsession-4.1.0.0-0.0x2go1.1.git20180302.1517.main.el6.x86_64
x2goserver-common-4.1.0.0-0.0x2go1.1.git20180302.1517.main.el6.x86_64
nxagent-3.5.99.14-0.0build1.1.git20180302.2954.main.el6.x86_64
nx-libs-3.5.99.14-0.0build1.1.git20180302.2954.main.el6.x86_64

NXAGENT - Version 3.5.99.14

Copyright (c) 2001, 2011 NoMachine (http://www.nomachine.com)
Copyright (c) 2008-2014 Oleksandr Shneyder <o.shneyder@phoca-gmbh.de>
Copyright (c) 2011-2016 Mike Gabriel <mike.gabriel@das-netzwerkteam.de>
Copyright (c) 2014-2016 Ulrich Sibiller <uli42@gmx.de>
Copyright (c) 2014-2016 Mihai Moldovan <ionic@ionic.de>
Copyright (c) 2015-2016 Qindel Group (http://www.qindel.com)
See https://github.com/ArcticaProject/nx-libs for more information.

Info: Agent running with pid '3568'.
Session: Starting session at 'Wed Mar  7 20:48:08 2018'.
Info: Proxy running in client mode with pid '3568'.
Info: Using errors file '/tmp/.x2go-testuser/C-testuser-51-1520448487_stDGNOME_dp32/session.log'.
Info: Using stats file '/tmp/.x2go-testuser/C-testuser-51-1520448487_stDGNOME_dp32/C-testuser-51-1520448487_stDGNOME_dp32/stats'.
Loop: WARNING! Unrecognized session type 'unix-kde-depth_32'. Assuming agent session.
Warning: Unrecognized session type 'unix-kde-depth_32'. Assuming agent session.
Info: Waiting for connection from 'localhost' on socket 'tcp:*:42588'.
Info: Accepted connection from '127.0.0.1'.
Info: Connection with remote proxy completed.
Info: Using ADSL link parameters 1408/24/1/0.
Info: Using agent parameters 5000/10/50/0/0.
Info: Using cache parameters 4/4096KB/8192KB/8192KB.
Info: Using pack method '16m-jpeg-9' with session 'unix-kde-depth_32'.
Info: Using ZLIB data compression 1/1/32.
Info: Using ZLIB stream compression 4/4.
Info: No suitable cache file found.
Info: Listening to X11 connections on display ':51'.
Info: Established X client connection.
Info: Using shared memory parameters 1/1/0/0K.
Info: Using alpha channel in render extension.
Info: Not using local device configuration changes.
Warning: Cannot read keystroke file '/home/testuser/.nx/config/keystrokes.cfg'.
Info: using keystrokes file '/etc/nxagent/keystrokes.cfg'
Warning: ignoring keystroke 'viewport_scroll_up' (already in use by 'viewport_move_up')
Warning: ignoring keystroke 'viewport_scroll_up' (already in use by 'viewport_move_up')
Warning: ignoring keystroke 'viewport_scroll_right' (already in use by 'viewport_move_right')
Warning: ignoring keystroke 'viewport_scroll_right' (already in use by 'viewport_move_right')
Warning: ignoring keystroke 'viewport_scroll_down' (already in use by 'viewport_move_down')
Warning: ignoring keystroke 'viewport_scroll_down' (already in use by 'viewport_move_down')
Current known keystrokes:
  close_session         Ctrl+Alt+t
  switch_all_screens    Ctrl+Alt+f
  fullscreen            Ctrl+Shift+Alt+f
  minimize              Ctrl+Alt+m
  defer                 Ctrl+Alt+e
  ignore                Ctrl+Alt+BackSpace
  force_synchronization Ctrl+Alt+j
  resize                Ctrl+Alt+r
  viewport_move_left    Ctrl+Shift+Alt+Left
  viewport_move_left    Ctrl+Shift+Alt+KP_Left
  viewport_move_up      Ctrl+Alt+Up
  viewport_move_up      Ctrl+Alt+KP_Up
  viewport_move_right   Ctrl+Alt+Right
  viewport_move_right   Ctrl+Alt+KP_Right
  viewport_move_down    Ctrl+Alt+Down
  viewport_move_down    Ctrl+Alt+KP_Down
  viewport_scroll_left  Ctrl+Alt+Left
  viewport_scroll_left  Ctrl+Alt+KP_Left
  reread_keystrokes     Ctrl+Alt+k
Info: keyboard file created: '/home/testuser/.x2go/C-testuser-51-1520448487_stDGNOME_dp32/keyboard'
Info: Keycode conversion auto-determined as off
Session: Session started at 'Wed Mar  7 20:48:16 2018'.
Info: Screen [0] resized to geometry [784x561] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [784x561] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [784x561] fullscreen [0].
Info: Screen [0] resized to geometry [784x561] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [784x561] fullscreen [0].
Info: Screen [0] resized to geometry [984x728] fullscreen [0].
Info: Screen [0] resized to geometry [984x728] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [984x728] fullscreen [0].
Info: Screen [0] resized to geometry [984x728] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [1856x1177] fullscreen [0].
Info: Screen [0] resized to geometry [984x728] fullscreen [0].
Info: Screen [0] resized to geometry [984x728] fullscreen [0].
Info: Screen [0] resized to geometry [1309x955] fullscreen [0].
Info: Screen [0] resized to geometry [1309x955] fullscreen [0].
Info: Screen [0] resized to geometry [1309x955] fullscreen [0].

[nkrepo]

More testing is done trying to identify if the 1 pixel hack is responsible for the flickering

1-pixal hack

Flickering also occurs when the the nx-nxagent is manually started
Started putty with x-forwarding and run
nxagent -ac :1
Started a second putty and run :

export DISPLAY=:1
STARTUP=mate-session dbus-run-session /etc/X11/Xsession

Tested with:
Vcxserv 1.19.6.0
Vcxserv 1.17.0.0-3
Xming 7.5.0.89

The flickering loop always occurs when the Window is maximized

Tested also with Cyxwin-X version 1.18.4-1 and the flicker loop does not occur.
It flickers only once after each window resize.

[nkrepo]

I build the Ubuntu packages from the latest source from nx-libs.git and enabled DEBUG and TEST in
nx-X11/programs/Xserver/hw/nxagent/Screen.c
nx-X11/programs/Xserver/hw/nxagent/test.c
and attached the log file from the nxagent.

nxagent_debug.log.gz

Modified nx-X11/programs/Xserver/hw/nxagent/Screen.c by removing

      /*RROutputChanged(pScrPriv->outputs[i], TRUE);
      RRCrtcChanged(pScrPriv->crtcs[i], TRUE);*/

And the flicker occurs again, the nxagent_debug-mod.log.gz file contains the output from the modified nxagent

nxagent_debug-mod.log.gz

From the vcxsrv.log noticed that after the (ConfigureWindow), error events follow

winMultiWindowWMProc - Error code: 8 (Match), ID: 0x002000cd, Major opcode: 12 (ConfigureWindow), Minor opcode: 0 ((null))
winMultiWindowWMProc - Error code: 3 (Window), ID: 0x002000d3, Major opcode: 25 (SendEvent), Minor opcode: 0 ((null))
winMultiWindowWMProc - Error code: 3 (Window), ID: 0x002000d3, Major opcode: 25 (SendEvent), Minor opcode: 0 ((null))
winMultiWindowWMProc - Error code: 3 (Window), ID: 0x002000d3, Major opcode: 25 (SendEvent), Minor opcode: 0 ((null))
winMultiWindowWMProc - Error code: 3 (Window), ID: 0x002000d3, Major opcode: 25 (SendEvent), Minor opcode: 0 ((null))
winMultiWindowWMProc - Error code: 8 (Match), ID: 0x002000cd, Major opcode: 12 (ConfigureWindow), Minor opcode: 0 ((null))
winMultiWindowWMProc - Error code: 3 (Window), ID: 0x002000d3, Major opcode: 25 (SendEvent), Minor opcode: 0 ((null))
winMultiWindowWMProc - Error code: 3 (Window), ID: 0x002000d3, Major opcode: 25 (SendEvent), Minor opcode: 0 ((null))
winMultiWindowWMProc - Error code: 3 (Window), ID: 0x002000d3, Major opcode: 25 (SendEvent), Minor opcode: 0 ((null))
winMultiWindowWMProc - Error code: 3 (Window), ID: 0x002000d3, Major opcode: 25 (SendEvent), Minor opcode: 0 ((null))
winMultiWindowWMProc - Error code: 8 (Match), ID: 0x002000cd, Major opcode: 12 (ConfigureWindow), Minor opcode: 0 ((null))
winMultiWindowWMProc - Error code: 3 (Window), ID: 0x002000d3, Major opcode: 25 (SendEvent), Minor opcode: 0 ((null))
winMultiWindowWMProc - Error code: 3 (Window), ID: 0x002000d3, Major opcode: 25 (SendEvent), Minor opcode: 0 ((null))
winMultiWindowWMProc - Error code: 3 (Window), ID: 0x002000d3, Major opcode: 25 (SendEvent), Minor opcode: 0 ((null))

vcxsrv.log

[uli42]

@nkrepo: please find a version printing more debugging output in this branch: https://github.com/uli42/nx-libs/tree/tst_flicker Can you please compile this version and supply another debug log?

[nkrepo]

@uli42 : I build and run the tst_flicker branch. I am attaching the log file bellow.

nxagent-tst_flicker.log

VCXSrv.0.log

[nkrepo]

Run nxagent with -sync option, attaching the new log, the same flicker loop happens when the window is maximized.

nxagent-tst_flicker-sync.log

[nkrepo]

I did a little more testing with different X-Servers
With latest Cygwin-X the flicker loop can be triggered when maximizing but not every time.
With Vcxsrv integrated with x2go the flicker loop can be triggered when maximizing but not not every time.
With Vcxsrv 1.17.0.0-3 the flicker loop is triggered every time when maximizing.

[nkrepo]

I did some more tests asked by @uli42 .
I tested with nxagent -rrxinerama, it made no difference, the flickering still happens, I am attaching the log bellow.
nxagent-rrxinerama.log
I figured out that the parameters "+bs -wm" have to be used with the vcxsrv to enable the backing store, but flickering still happens.

I also noticed that there no need to start the mate-session for the vcxsrv client window to start flickering.
I it flickers by just running the nxagent at the server side only and maximizing the client window.
vcxsrv client window flickering

[uli42]

I did some tests, too. And I could see that the x position of the nxagent window is changing back and forth between 0 and 8 while the y position is flapping between 23 and 31 (again 8 pixels) between those many ConfigureNotify events the nxagent receives. Searching for "windows 10 8pixels" lead me to this insane Windows 10 behaviour: https://stackoverflow.com/questions/42473554/windows-10-screen-coordinates-are-offset-by-7 (money quote: "In my opinion, whoever did this at Microsoft should be immediately shot.")

Digging in that direction now. Still, I don't have a good idea how to handle that.

Update: setting the VcXsrv executable to "Windows 7" in the compatibility tab changes the values from 8 to 4, the rest stays the same.

[uli42]

The other theory: Windows 10 changes the size of the window title bar when maximizing. The height is reduced and the program`s icon is moving a bit closer to the left edge. On my slow VM it looks like this done using multiple operations one after the other (move the icon to the left, reduce the height, move the window; I cannot define the order for sure). If every operation is causing an event this might be an explanation.

[sunweaver]

What happens if you disable all visual effects in Windows??? Mike

…

On Sunday, March 18, 2018, Ulrich Sibiller wrote: The other theory: Windows 10 changes the size of the window title bar when maximizing. The height is reduced and the program`s icon is moving a bit closer to the left edge. On my slow VM it looks like this done using multiple operations one after the other (move the icon to the left, reduce the height, move the window; I cannot define the order for sure). If every operation is causing an event this might be an explanation. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or mute the thread.

-- Sent from my Fairphone 2 (running Sailfish OS)

[uli42]

Unfortunately I haven't found where to do this yet. I have found some instructions but they were not valid anymore. Looks like MS has dropped that feature with one of the Win10 releases. Mike Gabriel <notifications@github.com> schrieb am Mo., 19. März 2018, 07:01:

…

What happens if you disable all visual effects in Windows??? Mike On Sunday, March 18, 2018, Ulrich Sibiller wrote: > The other theory: Windows 10 changes the size of the window title bar when maximizing. The height is reduced and the program`s icon is moving a bit closer to the left edge. On my slow VM it looks like this done using multiple operations one after the other (move the icon to the left, reduce the height, move the window; I cannot define the order for sure). If every operation is causing an event this might be an explanation. > — > You are receiving this because you are subscribed to this thread. > Reply to this email directly, view it on GitHub, or mute the thread. > -- Sent from my Fairphone 2 (running Sailfish OS) — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#600 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AGBw5HbkcE1f_9sPx3Rp7T_THW-NghZOks5tf0nIgaJpZM4RA9Op> .

[nkrepo]

@uli42 , yes of course, I will produce the new logs until tomorrow.
@sunweaver , I did a test with "Desktop Composition" , "Menu and window animation" and "Visual styles disabled", the flickering still occurs.

I have to note that after every client window resize (not maximizing), an extraneous client window resize event occurs to same geometry every time. It may worth to start looking for that first.

For example :

Info: Screen [0] resized to geometry [984x728] fullscreen [0].
Info: Screen [0] resized to geometry [984x728] fullscreen [0].