Issue #2949457 by idebr, jibran, Wim Leers, dungahk, fago, kim.pepper, neclimdul, ravi.shankar, Suresh Prabhu Parkala, Sam152, joshua1234511, Kristen Pol, kualee, MiroslavBanov, acbramley, alexpott, Fabianx: Enhance Toolbar's subtree caching so that menu links with CSRF token do not need one subtree cache item per session

Issue #1964880 by MiroslavBanov, jessebeach, falcon03, rteijeiro: Convert the Overlay close button from an anchor element to a button element.