Little minutes of research give already some insight.
/usr/share/xsessions/xfce4.desktop contains a line saying
Exec: startxfce4
A quick look at .xsession-errors reveals that this command tries to start an X server even though there is already an X server running gdm. Looks like startxfce4 is the wrong command to start a session.
Little minutes of research give already some insight.
/usr/share/ xsessions/ xfce4.desktop contains a line saying
Exec: startxfce4
A quick look at .xsession-errors reveals that this command tries to start an X server even though there is already an X server running gdm. Looks like startxfce4 is the wrong command to start a session.