What is the test for determining whether a spectator's actions were prejudicial to a jury?

"The trial court has broad discretion to ascertain whether a spectator's actions were prejudicial." (People v. Myles (2012) 53 Cal.4th 1181, 1215.) Only spectator misconduct that would have influenced a jury's verdict will warrant a new trial. (Ibid.) A court may instead conclude that a comment is so de minimis that even if the jury heard it, there was no possibility it would affect the verdict and prejudice a defendant. (People v. Trinh (2014) 59 Cal.4th 216, 250.)