What steps will reproduce the problem?
3.Pressing Ctrl-Z won't take an effect.
What is the expected output? What do you see instead?
Ctrl-Z should undo changes (even after file has been saved).
What version of the product are you using? On what operating system?
Please provide any additional information below.
Keep in mind, PN is PROGRAMMER's notepad and programmers often save files (in-fact every time when I run sctipt, I have to save file). So, ability to undo changes after saving file is VITAL for PN!
Thank you guys for good work! Especially for PyPN!