I feel like I am asking a lot of these kinds of questions.

Consider this scenario:

The use deletes a sketch. In my application I am tracking certain things in the sketch. Since the user deleted the sketch I delete the items I was tracking related to that sketch. Now the user undoes the delete > sketch. Now I need to know so I can take some sort of action to undo the deletion in my data.

Does anybody know how to determine if a delete > sketch was just undone? If so then what sketch?