Hi Martin, one way to keep it is after you see that it's gone use undo to go back a step so it will reappear then select it and use Cmd+C to copy it to the clipboard, then redo then Cmd+V paste. That's kind of a general purpose way to keep something that was removed by any command.

Or another possibility is to use boolean difference with that surface as the cutting object, there is a "Keep objects" checkbox in the command options that you can use for boolean difference where it won't remove the cutting object.

By the way I still have it on my list to investigate the file dialog thing you wrote about way further up in this thread I just haven't had a chance to do the testing for it quite yet.

- Michael