There are 6 previous versions of this script.
// ==UserScript==
// @name Muzzle
// @namespace http://www.yojimbo.fr
// @include https://mail.google.com/*
// @include http://mail.google.com/*
// ==/UserScript==
GM_addStyle(".vm { display: none !important; }");
GM_addStyle(".vl.vF { display: none !important; }");