Do you have references to it being rejected? I had not heard that until now.

>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.