use pack_end instead of pack_start

src/modules/sni/tray.cpp

@@ -25,7 +25,7 @@ Tray::Tray(const std::string& id, const Bar& bar, const Json::Value& config)
 }
 
 void Tray::onAdd(std::unique_ptr<Item>& item) {
-  box_.pack_start(item->event_box);
+  box_.pack_end(item->event_box);
   dp.emit();
 }