Index: wp-admin/css/colors-classic.css
===================================================================
--- wp-admin/css/colors-classic.css	(revision 11028)
+++ wp-admin/css/colors-classic.css	(working copy)
@@ -611,8 +611,8 @@
 	border-color: #BBD8E7;
 }
 
-.metabox-holder .postbox,
-#poststuff .postbox {
+.widget,
+.postbox {
 	background-color: #FFF;
 }