I would like to see an undo/redo history. This would allow me to select exactly what I want to undo/redo. Having an undo/redo history would save me time because I would not have to press undo/redo several times. I also would not be guessing what step I want to undo.

Also, Cartoon Animator can support up to 99 undos. Having this many undos is a pointless feature without an undo history. No one is going to take advantage of this feature if they must press the undo button 99 times.