xfce4-popup-windowmenu -V (return code: 1)
xfce4-panel: Cannot open display: .
Type "xfce4-panel --help" for usage.
xfce4-popup-windowmenu --help (return code: 0)
Usage:
xfce4-popup-windowmenu [OPTION...]
Options:
-p, --pointer Popup menu at current mouse position
-h, --help Show help options
-V, --version Print version information and exit