LightUp v3.0j
OSX 10.9 (Mavericks) breaks the way SketchUp plugins create dialogs and this was effecting LightUp. The result was the Preferences dialog on Macintosh running OSX 10.9 would be a blank window.
LightUp v3.0j resolves this issue and also has some minor fixes and improvements.
You can use your Registration Key to re-download a new installer with the latest version from Downloads