Hi Andrei - for undo what I mean is that you would not lose the ability to undo after you have saved the file and reopened it later.

Currently if you close a file you lose your undos, undos only are kept just in memory for the current file session. Once you close down MoI and start it later and reopen the same file it would be good if you could undo then the same as you could in the original session.

At first this would not have anything to do with removing just one step out of a sequence like you are describing with fillets though.

- Michael