For what it is worth there is a Windows User Experience Interaction Guidelines document that goes into great detail on how to ‘properly’ design a Windows UI. It will even tell you how many pixels a Cancel button should be from the lower and right side of a dialog.

With the advent of WPF and more unique / natural user interfaces I’m not sure how much coding to the specific guidelines matters any longer. However, I am assuming they take things such as this into account when certifying software for Windows Logo and the like.