be window dressing

To have the sole function of making a person or thing look or seem better than they really are. As far as I can tell, this new policy is little more than window dressing to woo new employees. He can dress in all the fancy suits he wants, but it's just window dressing in the end. It won't change the fact that he's a conceited jerk. That addition he's put on the house is just window dressing to distract from old the rest of the house is.