Sticky situation

 From:  wibble
I found a bug today!. Woot!

I'm sure other people have spotted it, yet didn't feel bothered enough to report it. Maybe you've spotted this yourself too, Michael:

When carrying out a loft or sweep operation, if you 'undo' the operation before selecting 'Done', there is then no way to cancel the operation. The only way to get out of the situation is to select another function. I suppose ideally I shouldn't be hitting 'undo' and I should select 'Cancel' instead. Yes, I know - I'm just awkward.