I absolutely love the history feature in Designer! It goes beyond any other similar tool that I've used in the past. However, I think there is a feature that could be added that would make it even better.
Problem:
When traversing your history, it is very easy to accidentally perform an action, like deselecting an object, thereby erasing all the other "future" actions from the history panel. From what I can tell, this cannot be undone.
Requested Feature:
Whenever you make a change while traversing your history, branch the history so that you are able to return to the original branch/path.