In 1948, Warners could no longer force theaters to buy their movies and shorts together as packages, due to the United States v. Paramount Pictures, Inc. anti-trust case that year. It resulted to shorts of the early 1960s to have tighter budgets. Davis' unit was shut down in 1949 by Warners due to budget issues, causing him to move to Freleng's unit to become one of his key animators. Edward Selzer in 1958, retired, leading to production manager John W. Burton to take his place. David DePatie assumed producer in 1960 after Burton left the studio.