Trouble for "soft kitty"

Soft kitty is the song that makes Sheldon on "The Big Bang Theory" feel comfortable.  It calms him when he's upset, sick, or tired.  It's been sung several times over the years on the series.  Now though, there's a controversy about it.  Edith Newlin's daughters claim that it is a poem that their mother wrote and is being used illegally.  But the publisher of the song in 1937 says that they legally licensed the song to Warner Brothers. Soft Kitty