this.type != "menu" ? this.type = "menu" : (popup => {

    var columns = [
        "¤ ¦ § © « » ¬ ® ° ± µ ¶ — ‘ ’ “ ” • ‰ ‹ › ™",
        "… ≈ ≠ × ✓ ✗ ⊞ ⊞ ⊞ ⊞ ⊞ ⊞ ⊞ ⊞ ⊞ ⊞ ⊞",
        "\uD83E\uDD8A \uD83D\uDE0E ⊞ ⊞ ⊞ ⊞ ⊞ ⊞ ⊞"
    ];
    var css = //0&&
    `
        #${_id} menuitem > .menu-text {
            font-size: 22px;
            font-family: Consolas, Rockwell, Verdana;
            text-align: center;
            -moz-appearance: none;
            margin: 0;
            padding: 0 14px;
        }
        #${_id} menuitem > :not(.menu-text) {
            display: none;
        }
        #${_id} > menupopup > arrowscrollbox {
            background-color: menu;
        }
    `.replace(/;/g, " !important;");

    var inserter = {
        get docShell() {
            delete this.docShell;
            return this.docShell = "docShell" in document
                && document.docShell instanceof Ci.nsIDocShell
                ? document.docShell : window.docShell;
        },
        get insertText() {
            delete this.insertText;
            return this.insertText = text => {
                if (!this.docShell.isCommandEnabled("cmd_insertText")) return;
                var params = "createCommandParams" in Components.utils
                    ? Cu.createCommandParams()
                    : Components.classes["@mozilla.org/embedcomp/command-params;1"]
                        .createInstance(Components.interfaces.nsICommandParams);
                params.setStringValue("state_data", text);
                this.docShell.doCommandWithParams("cmd_insertText", params);
            }
        },
        insert(text) {
            var br = document.activeElement;
            !br || br.localName != "browser" || !br.isRemoteBrowser
            ? this.insertText(text) : br.messageManager.loadFrameScript(
                `data:,(${this.insertText})${encodeURIComponent(text.toSource())}`
            , false, true);
        }
    };
    this.onmousedown = e => {
        if (e.button) return;
        popup.addEventListener("popupshowing", e => popup.firstChild
            .boxObject.parentBox.setAttribute("orient", "horizontal")
        , {once: true});
        popup.setAttribute("context", "");
        popup.setAttribute("oncommand", "inserter.insert(event.target.label);");
        popup.onauxclick = e => {
            var sym = e.target.label;
            sym && inserter.insert(sym);
        }
        popup.inserter = inserter;
        var df = document.createDocumentFragment();
        for(var symbols of columns) {
            var menugroup = popup.appendChild(document.createElement("menugroup"));
            menugroup.setAttribute("orient", "vertical");
            for(var sym of symbols.split(" ")) menugroup.appendChild(
                document.createElement("menuitem")
            ).setAttribute("label", sym);
        }
        popup.append(df);
        this.onmousedown = null;
        if (!css) return;
        var dwu = "windowUtils" in window && windowUtils instanceof Ci.nsIDOMWindowUtils
            ? windowUtils : window.QueryInterface(Ci.nsIInterfaceRequestor)
                .getInterface(Ci.nsIDOMWindowUtils);
        var type = dwu.AGENT_SHEET;
        var url = "data:text/css," + encodeURIComponent(css);
        dwu.loadSheetUsingURIString(url, type);
        addDestructor(() => dwu.removeSheetUsingURIString(url, type));
    }
})(this.appendChild(document.createElement("menupopup")));

//var css = //0&&
    `   #${_id} menuitem > .menu-text{
            font-size:22px;
            font-family:Consolas,Rockwell,Verdana;
            text-align:center;
            -moz-appearance:none;
            margin:0;
            padding:0 14px;}
        #${_id} menuitem > :not(.menu-text){display:none;}
        #${_id} > menupopup > arrowscrollbox{background-color:menu;}
    `.replace(/;/g, " !important;");