Next wallpaper	Set the next item from the wallpaper list as the desktop wallpaper. However, if you're set to a random sequence on the Walser General Options tab, it will just pick a random wallpaper.
Previous wallpaper	Set the previous item from the wallpaper list as the desktop wallpaper. However, if you're set to a random sequence on the Walser General Options tab, it will just pick a random wallpaper.
Random wallpaper	Set a random item from the wallpaper list as the desktop wallpaper.
Clear desktop	Remove wallpaper completely from the desktop.
Set this wallpaper	Set the item specified in the dialog shown by clicking the button as the desktop wallpaper.
	The others hotkeys are characterized by the names.

Select a hotkey combination and click the button to "lock" the setting so it can't be accidentally changed.

You will see an error message if the hotkey not available. For example, if you try F10 and that key is already taken, you'll see: