When using the direct IP to access the controller, the app changes into just a UI for that specific controller and this is why you are not seeing the site change menu. If you want to use the app on the desktop, we have several options. The first is using the browser based application. For Google Chrome, this runs as an extension to Chrome. For FireFox, this actually will install as an icon on your desktop and start menu for the app. They work across all platforms. The links are below:
We also support a native app on OS X available here: https://itunes.apple.com/us/app/sprinklers/id903464532?ls=1&mt=12
Any of the above solutions will allow you to have the same experience as your Android app on the desktop.
Furthermore, the Unified firmware will be adding a new feature soon allowing remotely controller stations. For example, one of your controller’s can be the “main” controller with the normal stations it has and in addition you can add remote stations and define the IP:Port and station ID of the remote controller.