debug: No running instance of xfce4-panel was found

1. clear the sessions in the cache folder
• rm -r ~/.cache/sessions
• save the sessions and logout
2. alt-F2, run the xfce4-panel, and logout

•  [False]

• (emacs:1550): Gtk-WARNING **: Unable to locate theme engine in module_path: "pixmap",

• The Unable to locate theme engine in module_path: "pixmap" messages are a known bug.
  To fix it, install the gtk2-engines-pixbuf package