I have a couple of operations in my WP7 app that I need to indicate to the end user as taking a while. 

In the Android world I would call the ProgressDialog, which causes the screen to dim and the phone-specific spinner animation and whatever message I want in the middle of the screen. 

Some searching indicates that the proper way to do this in Windows Phone 7 (Mango, anyway) is to use the [ProgressIndicator](https://stackoverflow.com/questions/8516995/windows-phone-7-equilvalent-of-androids-progress-dialog), so I went down that road.

The problem is that in my app I do not want to see the system tray. I am hiding it in the XAML and I want to use the entire 800x480, and as near as I can tell ProgressIndicator doesn't fly unless there's a visible SystemTray. 

Is there a way to use ProgressIndicator without SystemTray? (i.e., it shows up, translucently, across the top of the app and then goes away) Failing that, are there any other predefined and established ways of indicating something like a ProgressDialog in WP7?