Show the settings menu outside of XFCE

Hide settings menu only on desktop environment which have another
power manager, to make it appear on LXDE menu.

Signed-off-by: Eric Koegel <eric.koegel@gmail.com>

settings/xfce4-power-manager-settings.desktop.in

@@ -8,7 +8,7 @@ Icon=xfpm-ac-adapter
 Terminal=false
 Type=Application
 Categories=XFCE;GTK;Settings;DesktopSettings;X-XFCE-SettingsDialog;X-XFCE-HardwareSettings;
-OnlyShowIn=XFCE;
+NotShowIn=GNOME;KDE;Unity;
 StartupNotify=true
 X-XfcePluggable=true
 X-XfceHelpComponent=xfce4-power-manager