In fact, it doesn't seem to display any effects added in FCP, Motion or Livetype. This is from the manual
Pre-render any still images or effects you want to grade in Color
Color can?t display or process still images, certain motion settings, FXScript or FxPlug
filters, Final Cut Pro generators (including titles), Motion project files, or LiveType
project files. If you want to grade clips using these effects in Color, you need to render
those shots in Final Cut Pro as self-contained QuickTime .mov files, and edit them back
into your Final Cut Pro sequence to replace the original clips prior to sending the
project to Color. For more information about effects and features that aren?t compatible
with Color, see ?Limitations in Color? on page 37.
I tried putting a very obvious tint and then a mirror filter on a clip and displaying it in Color - no dice.