XFCE Shortcut problems

After installing XFCE i had multiple Problems with my hotkeys.

I installed XFCE on Ubuntu with
sudo apt-get install xubuntu-desktop

Every step can be added at
Open Menu -> Settings -> Keyboard -> Tab Application Shortcuts.

Media Keys

Next Track

Command: dbus-send --print-reply --dest=org.mpris.MediaPlayer2.spotify /org/mpris/MediaPlayer2 org.mpris.MediaPlayer2.Player.Next Key:
Press the Next Track Media key.

Previous Track

Command: dbus-send --print-reply --dest=org.mpris.MediaPlayer2.spotify /org/mpris/MediaPlayer2 org.mpris.MediaPlayer2.Player.Previous Key:
Press the Next Track Media key.

Play/Pause Track

Command: dbus-send --print-reply --dest=org.mpris.MediaPlayer2.spotify /org/mpris/MediaPlayer2 org.mpris.MediaPlayer2.Player.PlayPause
Key:
Press the Play/Pause Media key.

Stop Track

Command: dbus-send --print-reply --dest=org.mpris.MediaPlayer2.spotify /org/mpris/MediaPlayer2 org.mpris.MediaPlayer2.Player.Stop
Key:
Press the Stop Media key.

Source : man42.net Blogpost

Lockscreen and WhiskerMenu

Lockscreen

Command:
xflock4
Key:
Press the Super + L Combo for Windows Like Lock

WhiskerMenu open on Super

Command:
xfce4-popup-whiskermenu
Key:
Press the Super Key

Note: Super L will be displayed as Key, works still as intended.