diff --git a/src/wp-includes/css/editor.css b/src/wp-includes/css/editor.css
index e81c10acbe..dd18ff9286 100644
--- a/src/wp-includes/css/editor.css
+++ b/src/wp-includes/css/editor.css
@@ -237,13 +237,28 @@ div.mce-inline-toolbar-grp.mce-arrow-down:after {
 
 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 {