Apparently since the release of the RTW version of the Windows Phone 7 development tools there is some odd thing showing up in the page. It looks like some kind of numeric thing, and it appears on the right side along the top right edge. Here’s a screen shot:
It is not static, either. When something changes in the app (like a button is pressed), this item changes its appearance, as if it were changing its value. The reason I think this is a post-RTW issue is that in apps that I orginally created using the Beta release it doesn’t appear.
I am rather mystified by this, and wonder if it’s something that might find its way into the finished app.
UPDATE: I posted this as a question on the Windows Phone 7 developer forum, and got an answer in very short order. It turns out that the RTW tools automatically turn on the frame rate counter by default. This is a development tool which is supposed to help developers keep tabs on the efficiency of your app. This is nice; too bad I didn’t know it already.