During Holly's murder trial, an expert witness testifies that she is addicted to absinthe, a type of liquor that has been outlawed throughout the entire world because it causes insanity. In reality, absinthe was sold in a number of European countries at that time (mid-sixties) and in years since has become legally available in even more countries.
The goof item below may give away important plot points.
Charged with murder, Holly has no doubt met with her attorney dozens of times in the months preceding her court date. But for some reason, it isn't until the final day of her trial that she first learns the lawyer's name and discovers that he is actually her own grown son.