In an Debian server (running Debiwith XFCE4), I am running X11vnc as a RDP server so people can connect to it from using Windows Remote Desktop (either from Windows or OSX). My current configuration creates a new Xfce4 session for each client-server; if Alice connects to the server from Home, there will be a Xfce4 session A created. If Alice disconnects from Home, then connects back later, she can continue working from session A. However, if Alice goes to Work and connects back using the same credentials, a new Xfce4 session B is created, and is assigned to a new X11 :# (like :0, :1 etc.) display. Therefore, Alice cannot continue working. Worse, some software wouldn't simply open since their process is still running in session A, though invisible to Alice from work in session B.
I would like to creates only one Xfce4 session for Alice wherever she connects to, however she connects to (any OS, any RDP client), until she kills/terminates Xfce4-session herself, so she can always keep on previous work.
What is the simplest configuration for X11vnc to achieve this?