Ticket #29135: 29135.2.patch

wp-admin/css/customize-controls.css

@@ -36 +36 @@
         border-bottom: 1px solid #ddd;
 }
 
-#customize-controls .wp-full-overlay-sidebar-content {
-        overflow-y: auto;
-        overflow-x: hidden;
-}
-
 #customize-info {
         border: none;
         border-top: 1px solid #ddd;