using gxt 3.0 and trying to set body style but not taking effect.

VerticalLayoutContainer p = new VerticalLayoutContainer();
ContentPanel image = new ContentPanel();
image.setHeaderVisible(false);
image.setBodyStyle("background-color: transparent");
p.add(image);
MessageBox.add(p)

the background of image is white whereas background for p is blue (default)
wondering how to make the image transparent so its background is same as p