Custom Scrollbar CSS

Any idea why none of the properties for a custom scrolbar show up in popups in the visual studio editor? Not only do any of the scrollbar properties pop up, but when I return to the design view the scrollbar has changed, but when I run the application the scroll bar is normal again??? any ideas??

BODY {
SCROLLBAR-3DLIGHT-COLOR: black; SCROLLBAR-BASE-COLOR: white
}