Apple Final Cut Pro X (10.0.9) - Manual (Page 327)

Chapter 11 Advanced editing 327
4 Drag the clips left or right in the rows of the Angle Editor so that the sync points align vertically.
Sync point
Sync point
Drag the clip to align
the sync points.
If an angle contains more than one clip, you can easily select all clips in the angle so that you can
move them all at once. To do this, choose Select Clips in Angle from the pop-up menu next to
the angle name.
To select all clips in an angle,
choose Select Clips in Angle
from the pop-up menu.