External display scaling
I have a 2015 Retina MacBook Pro with an external 4k display (Asus PB287Q) and since updating to Sierra yesterday, I can no longer select scaling "resolutions" that are between 1920x1080 and 3840x2160. HD is way too big, 4K way too small. Please let there be a solution to this... I tried rebooting, and it actually brought back the correct options until I closed the lid, and now they are gone and won't come back.
This is what my display properties look like (alt-click Options):
MacBook Pro (Retina, 13-inch,Early 2015), macOS Sierra (10.12)