Forgive me for the truly beginner's question here, but I've been trying to find out what property it is on CEGUI elements (for example, a PushButton) that controls an odd 'Fade'-like effect at the top and bottom of buttons. I've attached a screenshot for clarification.
![Image](http://i.imgur.com/APXD2.png)
Please let me know if there's any other information needed, but I 'feel' like the solution to this should be so straightforward, I just don't know what properties control the effect.
Thank you!