user@server:~$ grep nxagentHandleSelectionRequestFromXServer /tmp/.x2go-localadmin/C-localadmin-50-1742895429_stDtwm_dp24/session.log
nxagentHandleSelectionRequestFromXServer: Received SelectionRequestEvent from real server: selection [529][CLIPBOARD] target [342][UTF8_STRING] requestor [display[nx,options=/tmp/.x2go-localadmin/C-localadmin-50-1742895429_stDtwm_dp24/options:50.0]/0xa0016a] destination [603][NX_CUT_BUFFER_SERVER] time [0]
nxagentHandleSelectionRequestFromXServer: this event has been sent by nxagent!
nxagentHandleSelectionRequestFromXServer: no local owner for selection [529] - denying request.
nxagentHandleSelectionRequestFromXServer: Received SelectionRequestEvent from real server: selection [529][CLIPBOARD] target [31][STRING] requestor [display[nx,options=/tmp/.x2go-localadmin/C-localadmin-50-1742895429_stDtwm_dp24/options:50.0]/0xa0016a] destination [603][NX_CUT_BUFFER_SERVER] time [0]
nxagentHandleSelectionRequestFromXServer: this event has been sent by nxagent!
nxagentHandleSelectionRequestFromXServer: no local owner for selection [529] - denying request.
nxagentHandleSelectionRequestFromXServer: Received SelectionRequestEvent from real server: selection [529][CLIPBOARD] target [342][UTF8_STRING] requestor [display[nx,options=/tmp/.x2go-localadmin/C-localadmin-50-1742895429_stDtwm_dp24/options:50.0]/0xa0016a] destination [603][NX_CUT_BUFFER_SERVER] time [0]
nxagentHandleSelectionRequestFromXServer: this event has been sent by nxagent!
nxagentHandleSelectionRequestFromXServer: no local owner for selection [529] - denying request.
nxagentHandleSelectionRequestFromXServer: Received SelectionRequestEvent from real server: selection [529][CLIPBOARD] target [31][STRING] requestor [display[nx,options=/tmp/.x2go-localadmin/C-localadmin-50-1742895429_stDtwm_dp24/options:50.0]/0xa0016a] destination [603][NX_CUT_BUFFER_SERVER] time [0]
nxagentHandleSelectionRequestFromXServer: this event has been sent by nxagent!
nxagentHandleSelectionRequestFromXServer: no local owner for selection [529] - denying request.


user@client:~$ xwininfo -id 529
X Error: 9: Bad Drawable
  Request Major code: 14
  ResourceID in failed request: 0x211
  Serial number of failed request: 3
xwininfo: error: No such window with id 0x211.
user@client:~$ xwininfo -id 31
X Error: 9: Bad Drawable
  Request Major code: 14
  ResourceID in failed request: 0x1f
  Serial number of failed request: 3
xwininfo: error: No such window with id 0x1f.
user@client:~$ xwininfo -id 0xa0016a

xwininfo: Window id: 0xa0016a (has no name)

  Absolute upper-left X:  2
  Absolute upper-left Y:  29
  Relative upper-left X:  0
  Relative upper-left Y:  0
  Width: 1919
  Height: 1200
  Depth: 24
  Visual: 0x21
  Visual Class: TrueColor
  Border width: 0
  Class: InputOutput
  Colormap: 0xa00151 (not installed)
  Bit Gravity State: ForgetGravity
  Window Gravity State: NorthWestGravity
  Backing Store State: NotUseful
  Save Under State: no
  Map State: IsViewable
  Override Redirect State: no
  Corners:  +2+29  -1919+29  -1919--29  +2--29
  -geometry 1919x1200+0+0

user@client:~$ xwininfo -id 603
X Error: 9: Bad Drawable
  Request Major code: 14
  ResourceID in failed request: 0x25b
  Serial number of failed request: 3
xwininfo: error: No such window with id 0x25b.