I have created a new version of Calc. I have incorporated a lot of the requested features. There are still a few little weird things, but all in all not bad. The drag and drop of operations was a little more difficult than I thought at first. Since I don't do a lot of coding with native front end apps, it was a little weird. I had a hard time mostly with the dropping of the operation onto the NSTextView. The control has the performDragOperation: method implemented, but no documentation that describes the drag type that the control is expecting.