Background
To change the background:
- Select a Style from the dropdown list
Background Styles
Faint Ruled will draw horizontal lines on the background in the 
color selected in the Appearance settings.
Solid Color allows you to choose a solid background color from the color dropdown list. 
The color will flood fill the background behind the icons on the launcher page.
 
Image allows you to select a picture to be displayed behind 
the launcher icons. The image source can be either built-in Wallpapers
or Your Images.  The picture will be scaled and tiled if it doesn't fit
the desktop dimensions.