New in Windows 8.1 1 of 10 from http://www.CUSTOMPC.ie
Being able to use your Desktop Wallpaper as your Start Menu background
The Start Button is back, down there in the corner. But that’s not as interesting to me as the ability to use your Desktop wallpaper as your Start Menu background. This might be hard to visualize, but the point is that if you hit the Start Button (or the Windows Key) you’ll immediately move to the big Start Menu. When the background of that menu is your same desktop wallpaper, the result is much less jarring than a bright background and makes the whole Windows 8.x experience much more comforting.
From the Start Menu, hit Windows-C, click Settings, then Personalization. You’ll see the menu fly out as in the picture below. Select the tiny thumbnail of your wallpaper. It’s the square with the birds in my picture here.