Something is poorly implemented with Windows UI on HDR, and Macbooks it all looks fine then HDR content just appears brighter, I think the rest of the UI becomes duller too at that point but on windows it feels like running HDR on the Windows desktop means the whole screen looks dull, least it does on my 5K HDR Dell.

Not sure if I'm missing a setting, but I end up having to manually turn HDR on before playing a game and off after.