for those that use the items in the "mesh" and "repair" drop downs, a simple undo button or maybe give you a preview first then an "ok" to commit to the changes button. i havent really used any of these features yet other than just when familiarizing myself with the software. i tried a few of the items in the repair section and the result was not at all what i wanted. i had to remove the model and drop a new one back on the bed to go back. just an observation
of course i could be missing something too.