Apple Logic Pro 9 - Manual (Page 486)

Extending a take region section (dragging the start point to the left or the end point to
the right) automatically shortens adjacent sections on other take regions. Shortening a
take region section (dragging the start point to the right or the end point to the left)
automatically extends adjacent sections on other take regions. This ensures that you do
not create silence between different take region sections.
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Place the pointer over the start or end point of a take region’s selected area, then Shift-drag
when the pointer turns into the length change icon.
Shortening a take region section (dragging the start point to the right or the end point
to the left) does not extend adjacent sections on other take regions. This allows you to
create silence between different take region sections.
486 Chapter 15 Editing Audio Take Recordings