Apple Final Cut Express 4 - Manual (Page 379)

Chapter 26 Three-Point Editing 379
VI
The clip in the Viewer is placed in the track above the destination track, starting at the
beginning of the clip that intersects the Timeline playhead, or at the sequence In point.
If there is no track above the destination track, one is created.
Before a
superimpose edit
After a
superimpose edit