Add picture into an inner layout in order to avoid parent resize

extension.js

@@ -273,7 +273,11 @@ class MonitorWidget extends PanelMenu.Button {
 	picture.set_size((width != -1)?width:initial_pixbuf.get_width(),
 		      (height != -1)?height:initial_pixbuf.get_height());
 
-	return picture;
+	// Pack it in a box to avoid picture resize
+	let box = new St.BoxLayout({});
+	box.add_child(picture);
+
+	return box;
     }
 
     _manageEventAction(action) {