One fundamental concept we've given up is "what you see is what you get". Open up a window from Windows 95 all the way to Windows 7 and things that behave different look different. The part of the window "inside" and the part of the window border you can click and drag to resize or move around are two different colors. The minimize, maximize, and close buttons are a different color from the part of the title bar you can click to move the window around. Not so anymore. The "close" button is now a visible X and an invisible rectangle around the X. The drag-able border of the window is an invisible radius surrounding the edge of a window. I hope the executive responsible for this rots in hell.