Microsoft was at pains to tell that this was actually performance optimization: This may seem like a very minor change, but the difference is noticeable on benchmarks, and, like it or not, magazine writers like to use benchmarks as an “objective” way of determining how good a product is. The reviewers choose the game, and we are forced to play it.” MSDN Blogs. In Windows 7, you now notice that even maximized windows have this transparency effect. What then happened to the ‘performance optimization’ explanation, in Windows 7 !? Hence my question : Why is transparency now retained, even when windows are maximized in Windows 7 ?