iMovie HD: UNDO, UNDO, UNDO, UNDO, UNDO, UNDO 4

iMovie HD: UNDO, UNDO, UNDO, UNDO, UNDO, UNDO +4

If you realize you've made a mistake while in iMovie, as long as you catch your mistake fairly quickly (and before you empty the iMovie HD's Trash), you may be in luck. That's because iMovie gives you 10 undos. Just press Command-Z again and again until you come to your mistake, or you reach the 10th undo (which ironically is usually just one step before your mistake). (Note: In Tiger the undos seem to be actually unlimited, but if you get to 10 and it stops, you didn't hear that from me.)