IANAL, but I think not. I think this because there have been a plethora of tools and libraries over the decades (think Tk, WxWidgets, and similar) that emulate

IANAL, but I think not. I think this because there have been a plethora of tools and libraries over the decades (think Tk, WxWidgets, and similar) that emulate the native look-and-feel of the OS and I believe a company has to defend it's IP/copyrights otherwise it implicitly loses the ability to do so in the future. See: https://www.varnumlaw.com/insights/enforce-your-intellectual-property-or-risk-losing-it/ https://www.varnumlaw.com/insights/enforce-your-intellectual... Consequently, this is why companies will so often be quick to "attack" random side projects people do targeting their IP (even very old IP). It isn't necessarily out of a malicious desire so much as a legal requirement. If they don't then a "serious" company can follow suit and then they have no ability to fight it. Edit: to be clear, obviously they _can_ sue.