There appears to be a texture to the glass of my iPad that was not present on my iPad 2 or with my iPhone 4. It is visible when scrolling on white backgrounds and it almost looks like the screen is dirty. The effect is similar to that of using an antiglare screen protector but much more subtle and not as uniform. Any idea what the cause of this may be? I'm thinking the underside of the glass is slightly dirty. Are others seeing this.