So in the old 2.8 there was a toggle somewhere to enable vertex colors of all objects in the scene.
I cant seem to find that in the new blender 2.8, which is a bit of a pain when trying to pick and match colors off other objects…
I don’t remember such button. Maybe, you are talking about multi-object editing.
Currently, it is not possible to paint several objects at same time.
Multi-object editing does not work with texture paint mode, vertex paint mode or sculpt mode.
But, except this inability of painting, there is still ability to show vertex colors of all objects by adding to all of them, same material referring to vertex color channel as a color attribute.
Maybe there was a suggestion to add to Shading popover a specific option to display only vertex colors.
But I d’on’t remember such thing was working in 2.8 alphas.
The ‘Textured’ view mode shows vertex colors when there’s no material, when the renderer is set to Blender Internal.
@Gibbz: Since both ‘Textured’ and Blender Internal have been intentionally removed, I doubt this would be considered an issue. You could maybe do a feature request, like maybe Lookdev mode should show vertex colours when no material is assigned.