If I recall correctly, every time you evaluate a cell, that cell is
"saved". The "Save" button just additionally saves any changes you've
made to cells since you evaluated them. I think that is how it works.
Thanks,
Jason
I think the ctrl-z behavior is just a feature of the browser, not of
Sage. The browser provides a minimal undo for textboxes. Of course,
when you refresh or close/reopen the worksheet, the browser doesn't
carry that undo info forward.
Thanks,
Jason
On the sagenb issue tracker: http://code.google.com/p/sagenb/issues/list
Thanks,
Jason