Optimizing the Resume Experience
Fast App Resume in your app should be implemented in a manner that ensures a predictable experience for the user. The behavior of your app when it is resumed should depend on the entry point of your app when it was initially launched from a cold start and the entry point when it was resumed.
There are two kinds of entry points. Primary entry points occur via a primary tile on the Start Experience or an app link in the App List or Games hub. Secondary entry points occur via a deep link from a secondary tile, a toast notification, or from an extensibility point such as a protocol handler.
The Windows Phone OS maintains a navigation history for your app. When the user taps the hardware Back button, the OS navigates ...