Quote Originally Posted by Requiem of a Madman View Post
I must agree and I have no idea how to change it either.
Wintermute has a fantastic themebuilder for Fantasy Grounds:

A couple of people (including me) have made a request for ICONS compatibility, and Wintermute has said they will look into it. I'm sure it will take some time, but I believe we'll eventually be able to make our own themes and make them available to others.