First color, second color third color, etc

[Stgoldberg at aol.com]

I have been puzzled by the color feature in the object inspector for some of 
the objects (e.g. images) which list the options of "First color, second 
color, third color etc." What does this do?   If I check off a color, nothing 
happens and the option disappears on leaving the object inspector.   Perhaps 
someone can clarify this.   Thanks.
Steve Goldberg