add manager for popup entry points

scripts/external/entries/menu.js

@@ -0,0 +1,27 @@
+import Menu from '/scripts/GUI/context_menus.js';
+import texts from "/scripts/strings/read.js";
+import ManagedSidebar from "./sidebar.js";
+
+export default class MenuEntry {
+     /* Create all entries. */
+	constructor() {
+		// Add the context menu.
+		this.menu = new Menu({title: (new texts(`entry_contextMenu`)).localized, contexts: [`all`], event: {"onClicked": MenuEntry.onclick}, hidden: true});
+	};
+
+     /* 
+	Enable the sidebar. 
+	*/
+	enable () {
+		this.menu.show();
+	}
+
+	/* Disable. */
+	disable () {
+		this.menu.remove();
+	}
+
+	static onclick() {
+		new ManagedSidebar();
+	};
+}