After Windows and Surface chief Panos Panay departed Microsoft last year, the software giant quickly split his two divisions into two different teams. It was a move designed to push Windows engineers to focus on more web and AI features under Mikhail Parakhin, who was previously responsible for Bing and ads. It didn’t work out.Six months after that shake-up, Windows and Surface are back together under a new leader, following frustrations from the very top of Microsoft. The shuffling comes just a...