UNDO!
I just called a buddy of mine who as SI up, and he quoted a page number from
their docs to me.. pg 1-142: "The History menu cell options (including Undo,
Redo, etc.) are only available in the Model, Actor and Matter modules.
– G
PS: I'm not going to belabor the point. I know that everyone wants an undo
function. It was on virtually everyone's wishlist.