Index: wp-admin/css/wp-admin.dev.css
===================================================================
--- wp-admin/css/wp-admin.dev.css	(revision 17545)
+++ wp-admin/css/wp-admin.dev.css	(working copy)
@@ -2013,7 +2013,6 @@
 .postbox {
 	position: relative;
 	min-width: 255px;
-	width: 99.5%;
 }
 
 #trackback_url {