Apple Logic Express 9 - Manual (Page 486)

To alternate selected comp areas between take lanes
µ
Click an unselected area of a take region to make that particular area active and part of
the comp.
This automatically deselects the same area in another take region. This is a quick way to
compare a comp area on one take region with the same comp area on another take
region.
You can remove take region sections, or entire take regions, from the comp sections at
the top of the take folder.
486 Chapter 15 Editing Audio Take Recordings