If this is true, why wouldn't Microsoft patent the taskbar or directory structure tree layout pattern in Explorer? I don't think you would be granted a design

If this is true, why wouldn't Microsoft patent the taskbar or directory structure tree layout pattern in Explorer? I don't think you would be granted a design (let alone utility) patent that is as broad as "green and yellow blocks have significance, is a grid of 5x6, and has a keyboard below". Not a lawyer though so what do I know