Fades and Crossfades : Trimming Clips that Include Fades or Crossfades : Trimming a Clip to a Fade Boundary
 
Trimming a Clip to a Fade Boundary
You can trim clips that are adjacent to fade and crossfade boundaries.
To trim a clip on a fade boundary:
*With the Trim tool, click the clip boundary and drag to trim the clip. The fade remains constant and follows the new clip boundary.
Dragging a clip boundary with the Trim tool
Result of trimming the clip