It now displays a menu item on the Shell's panel.

weather@venemo.net/extension.js

@@ -1 +1,66 @@
 
+const GLib = imports.gi.GLib;
+const Gio = imports.gi.Gio;
+const Lang = imports.lang;
+const Mainloop = imports.mainloop;
+const Cairo = imports.cairo;
+const Clutter = imports.gi.Clutter;
+const Shell = imports.gi.Shell;
+const St = imports.gi.St;
+const Gettext = imports.gettext.domain('gnome-shell');
+const _ = Gettext.gettext;
+
+const Util = imports.misc.util;
+const Main = imports.ui.main;
+const PanelMenu = imports.ui.panelMenu;
+const PopupMenu = imports.ui.popupMenu;
+const Calendar = imports.ui.calendar;
+
+
+function WeatherMenuButton() {
+    this._init();
+}
+
+WeatherMenuButton.prototype = {
+    __proto__: PanelMenu.Button.prototype,
+
+    _init: function() {
+    
+        // Panel icon
+        this._weatherIcon = new St.Icon({ icon_type: St.IconType.FULLCOLOR, icon_size: Main.panel.button.get_child().height - 4, icon_name: 'view-refresh-symbolic' });
+        if (Main.panel.actor.get_direction() == St.TextDirection.RTL) {
+            this._weatherIcon.set_style('padding-left: 5px;');
+        }
+        else {
+            this._weatherIcon.set_style('padding-right: 5px;');
+        }
+        
+        // Label
+        this._weatherInfo = new St.Label({ text: 'Loading weather...' });
+
+        // Panel menu item - the current class
+        let menuAlignment = 0.25;
+        if (St.Widget.get_default_direction() == St.TextDirection.RTL)
+            menuAlignment = 1.0 - menuAlignment;
+        PanelMenu.Button.prototype._init.call(this, menuAlignment);
+
+        // Putting it together
+        let topBox = new St.BoxLayout();        
+        topBox.add_actor(this._weatherIcon);
+        topBox.add_actor(this._weatherInfo);
+        this.actor.set_child(topBox);
+
+        let hbox = new St.BoxLayout();
+        this.menu.addActor(hbox);
+        
+        // Items
+        hbox.add_actor(new St.Label({ text: 'heyhey' }));
+
+    }
+};
+
+function main() {
+    this._weatherMenu = new WeatherMenuButton();
+    Main.panel._centerBox.add(this._weatherMenu.actor, { y_fill: true });
+}
+