This what you put into Deactivation
enent should be called. I would suggest to read Application lifecycle at MSDN. There are a lot of information, so I won't post it here.
You can surely set breakpoint at Deactivation event (according the disscusion in comments).
But Closing event is not called when you hit Start buton.
More usefull links:
- Windows Phone 8 Application Lifecycle
- Understanding the Windows Phone Application Execution : part 1, part 2, part 3.
If you are having problems check you App.xaml if those events are used:
<Application.ApplicationLifetimeObjects>
<!--Required object that handles lifetime events for the application-->
<shell:PhoneApplicationService
Launching="Application_Launching" Closing="Application_Closing"
Activated="Application_Activated" Deactivated="Application_Deactivated"/>
</Application.ApplicationLifetimeObjects>
And it wouldn't get called (instantly) if your App is set to run in Background (Location tracking). It can get called in specific circumstances.