iMovie '11: Locate source video for your project clips
You can quickly find the source video (Event) for any video clips you’re using in your project. This is particularly useful if you want to duplicate video in your project or add the same video clip to a different project.
To find the source video for a clip in your project:
In the Project browser, select the video clip whose source you want to locate.
Choose View > “Reveal in Event Browser”; the View menu appears in a light gray bar across the top of your computer screen.
The source video for the selected video clip in your project is outlined in yellow.