We are a small company that writes good software. When someone started producing software which operated much the same as ours and some of the screens were extremely close to our designs then we started getting a little annoyed. We mentioned the magic word of copyright. In return we were quoted Navitaire Inc v Easyjet Airline Co Ltd (no.3)  and SAS Institute Inc v World Programming Ltd C-406/10. These appears to say that as long as you have not had access to the original code and were not using original code then you can copy virtually anything else. It all seems wrong to me as if I bought a copy of Sage Accounts and then made my own version that operated virtually the same then I'm sure they would be kicking my door down. Has anyone had anything similar?