According to my previous question http://social.msdn.microsoft.com/Forums/en-US/winappswithcsharp/thread/c498e32d-8615-4d74-b4ff-978f3468d1de
I have found a App to change the start menu wallpaper, Decor 8, I fond that this App will take the full control for the start menu's wallpaper. That mean when i use this app to set customized wallpaper, I can't use the default setting page to reset the start menu anymore until I close the customized wallpaper. And another issue is that the color of log in screen will not be the same with the color of tiles.
Why will Decor 8 cause this issue, how did it take the full control on the start menu?