I spent too much time on this one today, doing a quick post to potentially save others folks the struggle of figuring this out.
If you’ve used Visual Studio to build Windows Phone Apps you’re familiar with this menu, it basically let’s you pick either an emulator or a device where you want to publish your app.
I was searching high-and-low for this in my tool bar and settings and just couldn’t find it. Then I remembered that I was launching both the Phone app and a service at the same time. Basically I had my solution configured to launch multiple apps, really nice way to debug your phone and service in the same solution but this modifies your toolbar.
Setting this back to “Single Startup Project” resolved the issue.
Hope this helps!