The union of two sets contains all the members of both sets with no duplicate members.
Note that since either of the specified sets can be a set with one member, the SetUnion function can be used to perform the same operation as the SetAddMember function.
You can also use the plus (+) operator for this operation. The following statement is the equivalent of the SetUnion statement in the following example:
COLORS WindowColors = BackGround + Foreground