App

The App selection option in the screens list corresponds to the app as a whole. The options that are available to you on this object are extremely limited, but it does give you access to the OnStart event. This is a really useful event as you can carry out particular actions when the app is loaded for the first time without the need for any interaction from the user.

This is commonly used to hydrate local caches of data so that the PowerApp is ready to serve data when it's finished loading. It can also be used to populate a cache so that it can be used for offline working. It is worth noting that this OnStart event will only run when the app is launched from the browser or from a mobile device; it will not fire when you're using preview mode in the studio.

Now that we have looked at App, let's look at the actual screen list.