Index: src/wp-admin/css/common.css
===================================================================
--- src/wp-admin/css/common.css	(revision 36167)
+++ src/wp-admin/css/common.css	(working copy)
@@ -114,6 +114,14 @@
 	clear: both;
 }
 
+/* modern clearfix */
+.nav-tab-wrapper:after, /* Back-compat for plugins */
+.wp-clearfix:after {
+	content: "";
+	display: table;
+	clear: both;
+}
+
 /* Hide visually but not from screen readers */
 .screen-reader-text,
 .screen-reader-text span,
@@ -2064,13 +2072,6 @@
 	line-height: inherit;
 }
 
-/* contain floats */
-.nav-tab-wrapper:after {
-	content: "";
-	display: table;
-	clear: both;
-}
-
 /*------------------------------------------------------------------------------
   26.0 - Misc
 ------------------------------------------------------------------------------*/