Apple Final Cut Pro X (10.1.2) - Manual (Page 272)

Chapter 10 Advanced editing 272
The way clips are grouped within the compound clip depends on where you selected the clips:
•
If you selected clips in an event: Final Cut Pro creates a new compound clip in the event
(in addition to the selected clips) and places duplicates of the selected clips in the new
compound clip horizontally, in the order in which you selected them. (For further instructions
on creating a compound clip in the Browser, see “Create an empty compound clip,” below.)
Selected clips in the Browser
New compound clip
Compound
clip contents
67% resize factor