There is currently a lot of discussion around the subject of copyright law. The situation as I understand it is that the Disney Corporation wants everything ever created by Walt to stay under copyright no matter how long he's been dead. They have the money to persuade people. So the time was extended. This put a bunch of stuff back under copyright, including music, that had already gone to public domain. This went to the Supreme Court for a decision on October 5.
San Francisco Classical Voice has a long discussion of this whole situation and how it affects music here and here.
I say Walt and his descendants have already made enough money off of Snow White.