theme_advanced_background_colors

This option controls the colors shown in the palette of background colors displayed by the background color button. The default is a palette of 40 colors. It should contain a comma separated list of color values to be presented.

Example of usage of the theme_advanced_background_colors option:

tinyMCE.init({
	...
	theme_advanced_background_colors : "FF00FF,FFFF00,000000"
});