helpcenter/Web/js/core/basemaster.init.js

$(function() {
    LanguageSelectorManager.init(), $(document).keyup(function(e) {
        if ($(".blockUI").is(":visible")) {
            var i;
            if (!n) var n = e;
            n.keyCode ? i = n.keyCode : n.which && (i = n.which), 27 == i && $.unblockUI()
        }
    })
});