To be fair: The Windows way is kinda consistent: If the environment definition was changed, everyone gets a window message. It's just that no one but explorer.e

To be fair: The Windows way is kinda consistent: If the environment definition was changed, everyone gets a window message. It's just that no one but explorer.exe cares about that and reacts, as far as I'm aware (Raymond Chen had a recent article mentioning exactly this). So, the OS tells everyone 'Hey, you totally could update your environment'. But your running instance of Skype or whatever just doesn't need to care.