set the base color of the IconView widget style for diverse states of the widget. Here is an example demonstrating how to set the background of an IconView widget to the same color as the parent ScrolledWindow widget:

    sw = gtk.ScrolledWindow()
    iconview = gtk.IconView()
    style = iconview.get_style().copy()
    style_sw = scrolled_window.get_style()
    for state in (gtk.STATE_NORMAL, gtk.STATE_PRELIGHT,gtk.STATE_ACTIVE):
        style.base[state] = style_sw.bg[gtk.STATE_NORMAL]
    iconview.set_style(style)