I'm developing Windows application. It is crypto-functioning notepad.

And its design(UI interface) is almost(approx 90%?) same with Microsoft Windows Notepad.

Differences are only some buttons and sub-windows for encryption and decryption.

I would like to distribute my program for non-commercial. In this case, can I use its UI interface legally?


  • 1
    Relevant U.S. case law: en.wikipedia.org/wiki/Lotus_Dev._Corp._v._Borland_Int%27l,_Inc. (It's quite favorable for you)
    – apsillers
    May 7, 2020 at 4:07
  • @apsillers It sounds like I can use!
    – 6991httam
    May 7, 2020 at 5:36
  • 2
    I’m voting to close this question because it's not clear that you're actually asking about anything that relates to the free software/open source movements. Non-commercial is not a FOSS term, and FOSS licenses do not restrict commercial activity. If you want to ask whether the interface of a program like Notepad can be copyrighted or trademarked, that should be asked at the Law site. May 8, 2020 at 1:49
  • Sorry about that. I was confusing about the concept of OSS and non-commercial.
    – 6991httam
    May 8, 2020 at 8:05

1 Answer 1


Almost all text editors have that look and feel. If your application were to violate MS copyrights, Microsoft would have already had many other text editors pulled from the market already.

  • 2
    Thank you for your answer. I agree with you but want to know in the eyes of the law.
    – 6991httam
    May 8, 2020 at 8:13

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