Grayscale hotkey not working

[spazzlo]

I've been trying to use the new WINDOWS+END hotkey for grayscale, but it does nothing!

I'm using windows 10 version 1803 build 17134.345 and f.lux version 4.84

[bklnlks]

same here, the grayscale mode is not working on my desktop windows (flux v484), whether i am attempting to activate it via the hotkey, or manually from within flux.

[Broadie]

I've turned grayscale on to try it, but now I can't turn it off again. I need to see the diffrerent colours on my calendar for example. I've tried WINDOWS+END again, hoping it workd in reverse, but it doesn't. Please help me f.lux.