Centralize menu button coordinate logic and replace popupwindows with dropdownmenu.

modules/menus/notifications/index.js

@@ -1,14 +1,12 @@
-import PopupWindow from "../PopupWindow.js";
+import DropdownMenu from "../DropdownMenu.js";
 const notifs = await Service.import("notifications");
 import { Controls } from "./controls/index.js";
 import { NotificationCard } from "./notification/index.js";
 
 export default () => {
-  return PopupWindow({
+  return DropdownMenu({
     name: "notificationsmenu",
-    visible: false,
     transition: "crossfade",
-    layout: "top-right",
     child: Widget.Box({
       class_name: "notification-menu-content",
       css: "padding: 1px; margin: -1px;",