diff --git a/wp-admin/css/wp-admin.dev.css b/wp-admin/css/wp-admin.dev.css
index 7289317ac0..1831f2de17 100644
--- a/wp-admin/css/wp-admin.dev.css
+++ b/wp-admin/css/wp-admin.dev.css
@@ -139,6 +139,8 @@ TABLE OF CONTENTS:
 
 .has-right-sidebar #post-body-content {
 	margin-right: 300px;
+	float: none;
+	width: auto;
 }
 
 /* 2 columns main area */