max@maxim:~$ xfce4-panel -q && PANEL_DEBUG=systray xfce4-panel
xfce4-panel(main): version 4.10.0 on gtk+ 2.24.10 (2.24.10), glib 2.32.3 (2.32.1)
xfce4-panel(module-factory): reading /usr/share/xfce4/panel/plugins
xfce4-panel(module-factory): reading /usr/share/xfce4/panel-plugins
xfce4-panel(application): found window manager after 1 tries
xfce4-panel(base-window): 0x21c90050: rgba colormap=0x21c52440, compositing=true
xfce4-panel(base-window): 0x21c90050: rgba colormap=0x21c52440, compositing=true
xfce4-panel(display-layout): 0x21c90050: display=:0.0{comp=true}, screen-0[0x21c540c8]=[1280,1024] (monitor-0=[0,0;1280,1024])
xfce4-panel(positioning): 0x21c90050: screen=0x21c540c8, monitors=1, output-name=(null), span-monitors=false, base=0,0
xfce4-panel(positioning): 0x21c90050: working-area: screen=0x21c540c8, x=0, y=0, w=1280, h=1024
xfce4-panel(struts): 0x21c90050: top=25, start_x=0, end_x=1279
xfce4-panel(applicationsmenu): XDG_MENU_PREFIX is set to "xfce-", menu environment is "XFCE"
xfce4-panel(module): new item (type=object-type, name=applicationsmenu, id=1)
xfce4-panel(module): new item (type=object-type, name=tasklist, id=2)
xfce4-panel(module): new item (type=object-type, name=separator, id=3)
xfce4-panel(external): register dbus path /org/xfce/Panel/Wrapper/4
xfce4-panel(module): new item (type=external-wrapper, name=systray, id=4)
xfce4-panel(external): systray-4: child spawned; pid=13837, argc=8
xfce4-panel(module): new item (type=object-type, name=separator, id=14)
xfce4-panel(module): new item (type=external-46, name=indicator, id=8)
xfce4-panel(external): indicator-8: child spawned; pid=13842, argc=8
xfce4-panel(module): new item (type=object-type, name=separator, id=7)
xfce4-panel(module): new item (type=object-type, name=clock, id=5)
xfce4-panel(module): new item (type=object-type, name=separator, id=6)
xfce4-panel(external): register dbus path /org/xfce/Panel/Wrapper/9
xfce4-panel(module): new item (type=external-wrapper, name=actions, id=9)
xfce4-panel(xfce4-indicator-plugin): compiled against libxfce4panel 4.9.2
xfce4-panel(external): actions-9: child spawned; pid=13847, argc=8
xfce4-panel(base-window): 0x21c90200: rgba colormap=0x21c52440, compositing=true
xfce4-panel(base-window): 0x21c90200: rgba colormap=0x21c52440, compositing=true
xfce4-panel(base-window): 0x21cc2048: rgba colormap=0x21c52440, compositing=true
xfce4-panel(display-layout): 0x21c90200: display=:0.0{comp=true}, screen-0[0x21c540c8]=[1280,1024] (monitor-0=[0,0;1280,1024])
xfce4-panel(positioning): 0x21c90200: screen=0x21c540c8, monitors=1, output-name=(null), span-monitors=false, base=25,528
xfce4-panel(positioning): 0x21c90200: working-area: screen=0x21c540c8, x=0, y=0, w=1280, h=1024
xfce4-panel(module): new item (type=object-type, name=separator, id=10)
xfce4-panel(module): new item (type=object-type, name=launcher, id=11)
xfce4-panel(systray): requested cells=0, rows=1, row_size=20, children=0
xfce4-panel(indicator): calling plugin construct function
xfce4-panel(module): new item (type=object-type, name=launcher, id=12)
xfce4-panel(module): new item (type=object-type, name=launcher, id=17)
xfce4-panel(systray): registered manager on screen 0
xfce4-panel(module): new item (type=object-type, name=launcher, id=18)
xfce4-panel(module): new item (type=object-type, name=launcher, id=21)

(xfce4-indicator-plugin:13842): libindicator-WARNING **: IndicatorObject class does not have an accessible description.
xfce4-panel(module): new item (type=object-type, name=separator, id=13)

(xfce4-indicator-plugin:13842): libindicator-WARNING **: IndicatorObject class does not have an accessible description.
xfce4-panel(module): new item (type=object-type, name=directorymenu, id=23)
xfce4-panel(module): new item (type=object-type, name=separator, id=22)
xfce4-panel(external): systray-4: child is embedded; 5 properties in queue
xfce4-panel(external): indicator-8: child is embedded; 5 properties in queue
xfce4-panel(external): actions-9: child is embedded; 5 properties in queue
xfce4-panel(systray): allocate rows=1, row_size=20, w=2, h=22, horiz=true, border=1

(xfce4-indicator-plugin:13842): Gtk-CRITICAL **: IA__gtk_widget_set_accel_path: assertion `GTK_IS_ACCEL_GROUP (accel_group)' failed

(xfce4-indicator-plugin:13842): Gtk-CRITICAL **: IA__gtk_widget_add_accelerator: assertion `GTK_IS_ACCEL_GROUP (accel_group)' failed

(xfce4-indicator-plugin:13842): Gtk-CRITICAL **: IA__gtk_widget_set_accel_path: assertion `GTK_IS_ACCEL_GROUP (accel_group)' failed

(xfce4-indicator-plugin:13842): Gtk-CRITICAL **: IA__gtk_widget_add_accelerator: assertion `GTK_IS_ACCEL_GROUP (accel_group)' failed
xfce4-panel(systray): socket sbxkb[0x20b7f818] (composited=false, relative-bg=false
xfce4-panel(systray): added sbxkb[0x20b7f818] icon
xfce4-panel(systray): requested cells=1.5, rows=1, row_size=20, children=0
xfce4-panel(systray): allocate rows=1, row_size=20, w=33, h=22, horiz=true, border=1
xfce4-panel(systray): allocated sbxkb[0x20b7f818] at (2,13;30,20)