Install Xrdp for VNC via Windows Remote Desktop
xrdp creates an RDP server on remote Linux PCs.
RDP client on laptop:
- Windows: factory installed
 - macOS: RDP client
 - Linux: 
apt install xfreerdp 
Setup Xrdp server: remote Linux PC has the Xrdp server. Install Xrdp and Openbox desktop
apt install xrdp openboxCreate ~/.xsession containing
exec openbox-sessionEnable xrdp with new config
service xrdp restartOpenbox will show a grey screen upon typing password at Xrdp login.
Right-click mouse to open menu.
If only a gray/black screen, try editing /etc/xrdp/startwm.sh on the remote PC:
#!/bin/sh
if [ -r /etc/default/locale ]; then
. /etc/default/locale
export LANG LANGUAGE
fi
exec openbox-session