1) Click the star mark on the upper left of the thumbnail in the thumbnail pane.
The clip is registered to [Favorites].
Click the star mark again to unregister it from [Favorites].
Drag and drop the clip in the thumbnail pane to the [Favorites] on the sidebar.
Clips registered to [Favorites] are automatically rated as three stars in [Rating].
The number of stars in [Rating] can be changed by clicking a star in the properties. Rating can be set up to five stars, and clips can be searched by the number of stars.