I can think of 3 different occasions. First was when the menu bar would show a bezel when you hovered over it, which didn't happen normally in Windows. The se

I can think of 3 different occasions. First was when the menu bar would show a bezel when you hovered over it, which didn't happen normally in Windows. The second was when the menu bar became detachable like a tool bar. That also wasn't supported by public Windows APIs. The third was Ribbon. That I can at least forgive a little more because it's a massive shift in UI/UX. But the first two instances were so subtle that most people wouldn't have noticed, which then begs the question, why even waste resources literally reinventing their own APIs?