Index: src/wp-includes/css/editor.css
===================================================================
--- src/wp-includes/css/editor.css	(revision 30325)
+++ src/wp-includes/css/editor.css	(working copy)
@@ -236,15 +236,30 @@
 
 div.mce-inline-toolbar-grp.mce-arrow-left:before,
 div.mce-inline-toolbar-grp.mce-arrow-left:after {
+	margin: 0;
+}
+
+div.mce-inline-toolbar-grp.mce-arrow-left:before {
 	left: 20px;
 }
+div.mce-inline-toolbar-grp.mce-arrow-left:after {
+	left: 21px;
+}
 
 div.mce-inline-toolbar-grp.mce-arrow-right:before,
 div.mce-inline-toolbar-grp.mce-arrow-right:after {
-	right: 11px;
 	left: auto;
+	margin: 0;
 }
 
+div.mce-inline-toolbar-grp.mce-arrow-right:before {
+	right: 20px;
+}
+
+div.mce-inline-toolbar-grp.mce-arrow-right:after {
+	right: 21px;
+}
+
 div.mce-inline-toolbar-grp.mce-arrow-full {
 	right: 0;
 }