Created attachment 3928 session file I start xfce. I open one or more applications such as terminal or thunar and mousepad ... I logout, then I login. None application is restored. By cons, if I leave also an application such as gedit, all applications are restored. I have note that in the session file, terminal, thunar, mousepad ... are recorded legacy while gedit is Client.
In fact, what is the difference between an Legacy and an Client application
The latest version of xfce4-session seems to have solved the problem