Apple Motion 4 - Manual (Page 365)

2 Press Delete.
You can also Control-click an object, then choose Delete from the shortcut menu.
All of the operations just described can also be performed with multiple tracks. For
example, rather than just moving one object from Group 1 to Group 3, you can select
two or three objects within Group 1 and move them all at once.
To select more than one object or group track
µ
Command-click each of the tracks in the Layers list that you want to include in your
selection.
Adding Objects to the Track Area
When you drag a new object to the track area, a drop menu appears and lets you choose
how the object should be incorporated into the project. Depending on where in track
area you drop the object, you see different options. If you drag to a group or object track
in the track area, you can choose Composite, Insert, or Overwrite. An additional Exchange
option becomes available when you exchange the same type of media (such as a
QuickTime movie, an image sequence, or an image file). For example, Exchange appears
when you drag a QuickTime movie to a QuickTime movie’s track.
Note: You can also add objects to the Timeline layers list. For more information, see
Adding Objects to the Timeline Layers List .
Once an object is added to a project using the Timeline, it appears in the layers list and
becomes a Timeline track. The new object can appear above or below an existing object;
where you release the mouse button determines placement of the new object.
365 Chapter 8 Using the Timeline