Update mailbox.css

data/web/css/mailbox.css

@@ -9,7 +9,7 @@ table.footable>tbody>tr.footable-empty>td {
   overflow: visible !important;
 }
 .table-responsive {
-  overflow: visible !important;
+  overflow-x: scroll !important;
 }
 .footer-add-item {
   display:block;