iMovie 3: Preview Button Does Not Preview Effect or Title

On some configurations, clicking the Preview button in iMovie 3 may not display a preview of the title or effect in the larger playback window.
Symptom

After selecting an effect or title in iMovie 3, clicking the Preview button does not render the preview in the large playback window as expected.


Solution

Update to iMovie 3.0.3 or later. It is available from the iMovie website (http://www.apple.com/imovie).
Published Date: Feb 18, 2012