Is it possible for a developer to lose rights to work on a self-created, open-source-licensed project after an outside company, developer, or organization copyrights (or takes some other legal action regarding) the same project?
I haven't heard of this happening, but it seems entirely possible that someone could independently develop a project and then have the rights to continue working on said project (or an idea/language/technology) taken away...
For example, when a project like Minecraft (but open-source-licensed, in this case,) is developed, and is later bought by a company like Microsoft, does this mean that Microsoft can say that Mojang (or Notch, for that matter,) no longer has rights to work on further Minecraft development?
Another example would be Oracle who bought the open-source MySQL database.
In other words, are copyrights still necessary for intellectual property alongside open source licensing?