Blender Version
Broken: blender-2.80.0-git.a3bc8690387b-windows64
Short description of error
I drew on 3 different keyframes and looked to see if onion skin is on in viewport overlays but it's already on by default. The onion skin doesnt appear in the viewport.
Exact steps for others to reproduce the error
-add a grease pencil > blank object
-draw on 3 different keyframes

