Apple Soundtrack Pro - Manual (Page 233)

Chapter 10 Working With Automation 233
To lengthen the Timeslice in increments:
m Click the left arrow to lengthen the beginning of the Timeslice in increments, or click
the right arrow to move the end of the Timeslice in increments.
To lengthen the Timeslice dynamically:
m Click the center area of the field (where the numbers are), then drag left to lengthen
the beginning of the Timeslice, or drag right to lengthen the end of the Timeslice.
For projects using Time-based format, the left and right arrows lengthen the Timeslice
in seconds. For projects using Beats-based format, the arrows lengthen the Timeslice
in beats.