Few companies seem to feel as free to violate Apple’s human interface guidelines as Apple itself. One thing that has annoyed me consistently for years now is the poor Undo support in iPhoto. You can make edit after edit to a photo, but as soon as you leave editing mode or export photo Boom! The edits are all committed, and the Undo stack is cleared. You better like your what you did because there’s now no going back. Or is there?
In fact, iPhoto does save the original, untouched file. To restore it select Photos/Revert to Original. I can’t believe how many years it took me to find this; and Undo is now an all-or-nothing operation. You still can’t undo the last change but leave the previous eleven intact. Why, oh why can’t iPhoto maintain the Undo stack over time? Single Undo was hot stuff in 1984 when the Mac introduced it, but in 2007 the state of the art has moved on. Anything less than unlimited undo that persists over program starts and stops is harassing users.