Playing around with AC12 (trying to learn it to work with a colleague), and going through the training guides, one thing I've noticed a few times is that the Undo command is rather selective in what it will and won't do?
For example, I edit a composite wall structure, change something in it and OK, but if I don't like what I then see on screen I can't undo the change? I have to either remember exactly what the setup was before I made the change, or save before I do the edit so I can close down and then reopen to be where I was, neither of which is particularly sophisticated or difficult but frankly silly.
Is there any particular reason why Archicad should not undo to the previous state, or is the undo queue not capable of handling this? I would have though it would be quite important to undo such changes given it would be quite easy to screw up a project this way!