Quoting Disturbedcomputer,
1) She didn't make any Graphic for that part
0r
2) Did not name it correctly
or
3) Something else
1. I did
2. I did
3. Bingo! I designed it that way. What you see there are bullet holes (emphasis on 'holes'), so you see your background through them until they become active.
What I think knotreeltight is seeing is the transparency I used behind the buttons showing through in IE9.
I designed this skin before IE9 was out, so it will not look right, the default transparent buttons make it look like crap.
...it needs updating.