xfwm4 failure and fix
Just fyi, on a recent restart of my testing machine with xfce, my
window manager appeared broken (no workspaces, no title bars, etc.).
Googling revealed that xfwm4, for reasons unexplained, had not been
restored when the session restarted. One suggestion was Alt-F2 which,
in xfce, brings up a window allowing one to run an application; but
text entry was broken. Another was to do 'rm -r ~/.cache/sessions'.
After doing that, and a restart, windows control is restored. Hope
that helps someone who encounters the same problem.