When no explicit color transform was set, ManagedDisplayWidget fell back to
the project's default input colorspace. For scene-referred reference spaces
like ACEScg / Linear this produced a raw, greenish image on the viewer
instead of a monitor-ready picture. Default to the OCIO config's default
display and view so the viewer looks correct out of the box, while still
honoring any Color Space / Display / View choice the user makes from the
context menu.
Mike-Solar
b3c124fe7a