I see the authors point, and I'm not a designer, but as a wp7 user, I have to disagree. Looking at his image comparison, with and without the circles, he's abs

I see the authors point, and I'm not a designer, but as a wp7 user, I have to disagree. Looking at his image comparison, with and without the circles, he's absolutely right that without the circle it is easier to see the image. However, which looks nicer? I'm sure there was discussion at MS about which to chose, and it won't be the first time that visual appeal won out over function. As an example, the lack of strain relief on Apple cables (and unfortunately many other companies have followed). Another issue with the lack of the circle in theory is that it allows designers/developers to believe that they have free reign over this space. The circle may be as much of a hint to designers that they are limited to these areas to keep the UI as clean as possible.