All process are lxpanels subprocess

[sulincix]

my pstree output

sulin@DonkeyHUB:sulin :) > pstree
init─┬─ModemManager───2*[{ModemManager}]
     ├─NetworkManager───2*[{NetworkManager}]
     ├─accounts-daemon───2*[{accounts-daemon}]
     ├─agent───2*[{agent}]
     ├─at-spi-bus-laun─┬─dbus-daemon
     │                 └─3*[{at-spi-bus-laun}]
     ├─at-spi2-registr───2*[{at-spi2-registr}]
     ├─14*[busybox]
     ├─console-kit-dae───64*[{console-kit-dae}]
     ├─2*[dbus-daemon]
     ├─2*[dbus-launch]
     ├─dconf-service───2*[{dconf-service}]
     ├─elogind-daemon
     ├─gnome-terminal-─┬─bash───pstree
     │                 └─3*[{gnome-terminal-}]
     ├─gvfs-udisks2-vo───3*[{gvfs-udisks2-vo}]
     ├─gvfsd─┬─gvfsd-network───2*[{gvfsd-network}]
     │       ├─gvfsd-trash───2*[{gvfsd-trash}]
     │       └─2*[{gvfsd}]
     ├─gvfsd-metadata───2*[{gvfsd-metadata}]
     ├─light-locker───3*[{light-locker}]
     ├─lightdm─┬─Xorg───4*[{Xorg}]
     │         ├─lightdm─┬─lxsession─┬─lxclipboard
     │         │         │           ├─lxpanel─┬─Telegram───17*[{Telegram}]
     │         │         │           │         ├─firefox-bin─┬─Privileged Cont───24*[{Privileged Cont}]
     │         │         │           │         │             ├─Web Content───28*[{Web Content}]
     │         │         │           │         │             ├─Web Content───16*[{Web Content}]
     │         │         │           │         │             ├─WebExtensions───22*[{WebExtensions}]
     │         │         │           │         │             └─57*[{firefox-bin}]
     │         │         │           │         ├─gedit───4*[{gedit}]
     │         │         │           │         ├─gnome-screensho───3*[{gnome-screensho}]
     │         │         │           │         └─3*[{lxpanel}]
     │         │         │           ├─lxpolkit───2*[{lxpolkit}]
     │         │         │           ├─openbox
     │         │         │           ├─pcmanfm───2*[{pcmanfm}]
     │         │         │           ├─xscreensaver
     │         │         │           └─2*[{lxsession}]
     │         │         └─2*[{lightdm}]
     │         └─2*[{lightdm}]
     ├─login───bash
     ├─menu-cached───2*[{menu-cached}]
     ├─nm-applet───3*[{nm-applet}]
     ├─polkitd───7*[{polkitd}]
     ├─ssh-agent
     ├─supervise-daemo───dbus-daemon
     ├─2*[udevd]
     ├─udisksd───4*[{udisksd}]
     ├─wpa_supplicant
     ├─xfce4-notifyd───2*[{xfce4-notifyd}]
     └─xfconfd───2*[{xfconfd}]

[sulincix]

gnome-terminal uses own daemon (starting from dbus-launch) so gnome-terminal is not subprocess.

All process (started from panel) are lxpanels subprocess.

[LStranger]

That is actually correct, if you started some process by clicking in the panel, that process was spawned by panel.
No other option is available except making them like system daemons, i.e. bouncing them to init process.