>>I don't think this is correct. I seem to remember Fox Software working on the patent before it merged with Microsoft.

>Yes, Fox Software had applied for a patent. It was pending when purchased by Microsoft. Some years later the patent was rejected; it depended on too much "prior art". The technique used is known and has been incorporated into other products. The copyright would apply to the code that produces VFP -- if another implementation is created in a clean room (meaning no reverse engineering) then it is not a violation of copyright.

I remembered after I had made my first reply to this post, that the key thing that Dave Fulton had done was find techniques from mainframes and apply them to PCs. So, that they were denied patents is no surprise.
Oddly after adding my 2 cents, I found the below article which helps shed some light on the confusion between whether software is patented or copyrighted.

http://money.cnn.com/magazines/fortune/fortune_archive/2007/05/28/100033867/index.htm?source=yahoo_quote