I confirm that this is the case. I am using an Ubuntu 18.04 system and cairo-dock 3.4.1. As soon as any of the FreeOffice suite apps is run, cairo-dock opens its config dialog. On closing this, it opens again. On closing it, it remains closed. Here are the debug messages when I try to run cairo-dock from the terminal with the -l option set to debug:

  gldi_module_activate (Animated icons)
message :  (/build/cairo-dock-plug-ins-VqUvWF/cairo-dock-plug-ins-3.4.1/Animated-icons/src/applet-init.c:init:50)  
  init (/home/pramathesh/.config/cairo-dock/current_theme/plug-ins/Animated-icons/Animated-icons.conf)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-backends-manager.c:cairo_dock_register_animation:436)  
  cairo_dock_register_animation (bounce)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-backends-manager.c:cairo_dock_register_animation:436)  
  cairo_dock_register_animation (spot)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-backends-manager.c:cairo_dock_register_animation:436)  
  cairo_dock_register_animation (blink)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-backends-manager.c:cairo_dock_register_animation:436)  
  cairo_dock_register_animation (rotate)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-backends-manager.c:cairo_dock_register_animation:436)  
  cairo_dock_register_animation (wave)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-backends-manager.c:cairo_dock_register_animation:436)  
  cairo_dock_register_animation (wobbly)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-backends-manager.c:cairo_dock_register_animation:436)  
  cairo_dock_register_animation (pulse)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-backends-manager.c:cairo_dock_register_animation:436)  
  cairo_dock_register_animation (busy)
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-module-manager.c:gldi_module_activate:289)  
  gldi_module_activate (icon effects)
message :  (/build/cairo-dock-plug-ins-VqUvWF/cairo-dock-plug-ins-3.4.1/icon-effect/src/applet-init.c:init:67)  
  init (/home/pramathesh/.config/cairo-dock/current_theme/plug-ins/icon-effect/icon-effect.conf)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-backends-manager.c:cairo_dock_register_animation:436)  
  cairo_dock_register_animation (fire)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-backends-manager.c:cairo_dock_register_animation:436)  
  cairo_dock_register_animation (stars)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-backends-manager.c:cairo_dock_register_animation:436)  
  cairo_dock_register_animation (rain)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-backends-manager.c:cairo_dock_register_animation:436)  
  cairo_dock_register_animation (snow)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-backends-manager.c:cairo_dock_register_animation:436)  
  cairo_dock_register_animation (storm)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-backends-manager.c:cairo_dock_register_animation:436)  
  cairo_dock_register_animation (firework)
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-applications-manager.c:cairo_dock_register_appli:464)  
  cairo_dock_register_appli (0x5578cc4920e0 ; LibreOffice)
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_add_appli_icon_to_class:196)  
  cairo_dock_add_appli_icon_to_class (libreoffice-startcenter)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-application-facility.c:gldi_appli_icon_insert_in_dock:277)  
  gldi_appli_icon_insert_in_dock (LibreOffice, 0x5578cc4920e0)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-application-facility.c:_get_parent_dock_for_appli:187)  
  _get_parent_dock_for_appli (LibreOffice)
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_get_classmate:823)  
  cairo_dock_get_classmate (libreoffice-startcenter)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-application-facility.c:_get_parent_dock_for_appli:194)  
    no classmate for libreoffice-startcenter
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-dock-factory.c:_insert_icon:2065)  
  insert LibreOffice in _MainDock_
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-dock-factory.c:_insert_icon:2065)  
  insert (null) in _MainDock_
message :  (/build/cairo-dock-plug-ins-VqUvWF/cairo-dock-plug-ins-3.4.1/illusion/src/applet-notifications.c:cd_illusion_free_data:212)  
  
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-dock-factory.c:_insert_icon:2065)  
  insert (null) in _MainDock_
message :  (/build/cairo-dock-plug-ins-VqUvWF/cairo-dock-plug-ins-3.4.1/illusion/src/applet-notifications.c:cd_illusion_free_data:212)  
  
message :  (/build/cairo-dock-plug-ins-VqUvWF/cairo-dock-plug-ins-3.4.1/illusion/src/applet-notifications.c:cd_illusion_free_data:212)  
  
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-application-facility.c:gldi_appli_icon_insert_in_dock:310)  
   insertion de LibreOffice complete (0.00 56.00x56.00) dans _MainDock_
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-applications-manager.c:cairo_dock_register_appli:464)  
  cairo_dock_register_appli (0x5578cc427500 ; Win [Running] - Oracle VM VirtualBox)
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_add_appli_icon_to_class:196)  
  cairo_dock_add_appli_icon_to_class (virtualbox machine)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-application-facility.c:gldi_appli_icon_insert_in_dock:277)  
  gldi_appli_icon_insert_in_dock (Win [Running] - Oracle VM VirtualBox, 0x5578cc427500)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-application-facility.c:_get_parent_dock_for_appli:187)  
  _get_parent_dock_for_appli (Win [Running] - Oracle VM VirtualBox)
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_get_classmate:823)  
  cairo_dock_get_classmate (virtualbox machine)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-application-facility.c:_get_parent_dock_for_appli:194)  
    no classmate for virtualbox machine
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-dock-factory.c:_insert_icon:2065)  
  insert Win [Running] - Oracle VM VirtualBox in _MainDock_
message :  (/build/cairo-dock-plug-ins-VqUvWF/cairo-dock-plug-ins-3.4.1/illusion/src/applet-notifications.c:cd_illusion_free_data:212)  
  
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-application-facility.c:gldi_appli_icon_insert_in_dock:310)  
   insertion de Win [Running] - Oracle VM VirtualBox complete (0.00 56.00x56.00) dans _MainDock_
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-applications-manager.c:cairo_dock_register_appli:464)  
  cairo_dock_register_appli (0x5578cc485830 ; Glx-Dock / Cairo-Dock - Debugging cairo-dock-session? - Mozilla Firefox)
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_add_appli_icon_to_class:196)  
  cairo_dock_add_appli_icon_to_class (firefox)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-application-facility.c:gldi_appli_icon_insert_in_dock:277)  
  gldi_appli_icon_insert_in_dock (Glx-Dock / Cairo-Dock - Debugging cairo-dock-session? - Mozilla Firefox, 0x5578cc485830)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_prevent_inhibited_class:419)  
  >>> Firefox Web Browser will take an indicator during the next redraw ! (pAppli : 0x5578cc485830)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:_cairo_dock_set_same_indicator_on_sub_dock:286)  
    for the sub-dock Internet : indicator <- 1
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-application-facility.c:gldi_appli_icon_insert_in_dock:285)  
   -> se fait inhiber
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-applications-manager.c:cairo_dock_register_appli:464)  
  cairo_dock_register_appli (0x5578cc42c870 ; Downloads - /home/pramathesh/Downloads)
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_add_appli_icon_to_class:196)  
  cairo_dock_add_appli_icon_to_class (nemo)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-application-facility.c:gldi_appli_icon_insert_in_dock:277)  
  gldi_appli_icon_insert_in_dock (Downloads - /home/pramathesh/Downloads, 0x5578cc42c870)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_prevent_inhibited_class:419)  
  >>> Trash Can will take an indicator during the next redraw ! (pAppli : 0x5578cc42c870)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-application-facility.c:gldi_appli_icon_insert_in_dock:285)  
   -> se fait inhiber
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-applications-manager.c:cairo_dock_register_appli:464)  
  cairo_dock_register_appli (0x5578cc471320 ; Drafts — Evolution)
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_add_appli_icon_to_class:196)  
  cairo_dock_add_appli_icon_to_class (evolution)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-application-facility.c:gldi_appli_icon_insert_in_dock:277)  
  gldi_appli_icon_insert_in_dock (Drafts — Evolution, 0x5578cc471320)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_prevent_inhibited_class:419)  
  >>> Evolution will take an indicator during the next redraw ! (pAppli : 0x5578cc471320)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-application-facility.c:gldi_appli_icon_insert_in_dock:285)  
   -> se fait inhiber
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-applications-manager.c:cairo_dock_register_appli:464)  
  cairo_dock_register_appli (0x5578cc443650 ; Untitled 1 - TextMaker)
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_add_appli_icon_to_class:196)  
  cairo_dock_add_appli_icon_to_class (tm)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-application-facility.c:gldi_appli_icon_insert_in_dock:277)  
  gldi_appli_icon_insert_in_dock (Untitled 1 - TextMaker, 0x5578cc443650)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-application-facility.c:_get_parent_dock_for_appli:187)  
  _get_parent_dock_for_appli (Untitled 1 - TextMaker)
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_get_classmate:823)  
  cairo_dock_get_classmate (tm)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-application-facility.c:_get_parent_dock_for_appli:194)  
    no classmate for tm
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-dock-factory.c:_insert_icon:2065)  
  insert Untitled 1 - TextMaker in _MainDock_
message :  (/build/cairo-dock-plug-ins-VqUvWF/cairo-dock-plug-ins-3.4.1/illusion/src/applet-notifications.c:cd_illusion_free_data:212)  
  
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-application-facility.c:gldi_appli_icon_insert_in_dock:310)  
   insertion de Untitled 1 - TextMaker complete (0.00 56.00x56.00) dans _MainDock_
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-applications-manager.c:cairo_dock_register_appli:464)  
  cairo_dock_register_appli (0x5578cc40a210 ; pramathesh@niranjan-ub: ~)
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_add_appli_icon_to_class:196)  
  cairo_dock_add_appli_icon_to_class (gnome-terminal)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-application-facility.c:gldi_appli_icon_insert_in_dock:277)  
  gldi_appli_icon_insert_in_dock (pramathesh@niranjan-ub: ~, 0x5578cc40a210)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_prevent_inhibited_class:419)  
  >>> Terminal will take an indicator during the next redraw ! (pAppli : 0x5578cc40a210)
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-application-facility.c:gldi_appli_icon_insert_in_dock:285)  
   -> se fait inhiber
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/implementations/cairo-dock-X-manager.c:_on_update_applis_list:299)  
   cette fenetre (69208177) de la pile n'est pas dans la liste
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/implementations/cairo-dock-X-utilities.c:cairo_dock_xwindow_is_fullscreen_or_hidden_or_maximized:1334)  
  this appli should not be in taskbar anymore
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/implementations/cairo-dock-X-manager.c:_make_new_actor:175)  
  a shy window
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/implementations/cairo-dock-X-manager.c:_on_update_applis_list:299)  
   cette fenetre (69208189) de la pile n'est pas dans la liste
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/implementations/cairo-dock-X-utilities.c:cairo_dock_xwindow_is_fullscreen_or_hidden_or_maximized:1334)  
  this appli should not be in taskbar anymore
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/implementations/cairo-dock-X-manager.c:_make_new_actor:175)  
  a shy window
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-draw-opengl.c:cairo_dock_render_one_icon_opengl:318)  
  g_pGradationTexture(1) <- 47
message :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/implementations/cairo-dock-X-manager.c:_remove_old_applis:268)  
  cette fenetre (69208189, 0x5578cd715ac0, (null)) est trop vieille (12 / 13)
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-dock-facility.c:_cairo_dock_load_default_background:1299)  
  _cairo_dock_load_default_background ((null), 0, 21x14)
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-dock-facility.c:_cairo_dock_load_default_background:1299)  
  _cairo_dock_load_default_background ((null), 0, 21x14)
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-dock-facility.c:_cairo_dock_load_default_background:1299)  
  _cairo_dock_load_default_background ((null), 0, 21x14)
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-dock-facility.c:_cairo_dock_load_default_background:1299)  
  _cairo_dock_load_default_background ((null), 0, 21x14)
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-dock-facility.c:_cairo_dock_load_default_background:1299)  
  _cairo_dock_load_default_background ((null), 0, 21x14)
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_guess_class:1651)  
  cairo_dock_guess_class ((null), 'libreoffice-startcenter')
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_guess_class:1766)  
   -> 'libreoffice-startcenter'
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_register_class_full:1871)  
  + parsing class desktop file /usr/share/applications/libreoffice-startcenter.desktop...
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_register_class_full:1971)  
   -> class 'libreoffice-startcenter'
cairo_dock_create_surface_from_xpixmap: assertion 'Xid > 0' failed
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_create_surface_from_class:624)  
  cairo_dock_create_surface_from_class (libreoffice-startcenter)
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_create_surface_from_class:629)  
  bUseXIcon:0
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_create_surface_from_class:671)  
  get the class icon (libreoffice-startcenter)
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_guess_class:1651)  
  cairo_dock_guess_class ((null), 'virtualbox machine')
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_guess_class:1766)  
   -> 'virtualbox machine'
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_register_class_full:1866)  
  couldn't find the desktop file virtualbox machine
cairo_dock_create_surface_from_xpixmap: assertion 'Xid > 0' failed
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_create_surface_from_class:624)  
  cairo_dock_create_surface_from_class (virtualbox machine)
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_create_surface_from_class:629)  
  bUseXIcon:0
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_create_surface_from_class:682)  
  no icon for the class virtualbox machine
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_create_surface_from_class:698)  
  class virtualbox machine will take the X icon
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_guess_class:1651)  
  cairo_dock_guess_class ((null), 'tm')
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_guess_class:1766)  
   -> 'tm'
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_register_class_full:1866)  
  couldn't find the desktop file tm
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_create_surface_from_class:624)  
  cairo_dock_create_surface_from_class (tm)
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_create_surface_from_class:629)  
  bUseXIcon:0
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_create_surface_from_class:682)  
  no icon for the class tm
debug   :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/gldit/cairo-dock-class-manager.c:cairo_dock_create_surface_from_class:698)  
  class tm will take the X icon
warning :  (/build/cairo-dock-2Q_KQp/cairo-dock-3.4.1/src/cairo-dock.c:_cairo_dock_intercept_signal:180)  
  Cairo-Dock has crashed (sig 11).
It will be restarted now.
Feel free to report this bug on glx-dock.org to help improving the dock!
info on the system :
Linux niranjan-ub 4.15.0-33-generic #36-Ubuntu SMP Wed Aug 15 16:00:05 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
Couldn't guess if it was an applet's fault or not. It may have crashed inside the core or inside a thread
restarting with 'cairo-dock -l debug -m -q 5'...
Sorry, Cairo-Dock has encoutered some problems, and will quit.