Photoshop 2017/2018 '15 MBP Retina Adjustment Layers don't preview
I've had this problem for a while now. And now it is starting to piss me off. Photoshop CC 2017 and 2018. 2015 Retina Macbook Pro with 16GB RAM, MacOS Sierra 10.12.6 (16G1036).
If I make an adjustment layer, let's say convert to B&W for arguments' sake, the adjustment doesn't preview until I resize the window or something. Happens with ALL adjustment layer types. See attached screenshot. Why is the image still color when a BW adjustment layer has been applied?

