When will a judge order a confidential in camera showing in support of a motion to appoint a second attorney?

In making this determination the trial court must recognize that while ex parte hearings may be necessary to protect a defendant's rights (see, e.g., Keenan v. Superior Court, supra, 31 Cal.3d 424, 430, 180 Cal.Rptr. 489, 640 P.2d 108 [where the court sanctioned a defendant's confidential in camera showing, to avoid undue disclosure of defense strategy, in support of an application for the appointment of a second attorney] ), it does not follow that the prosecutor (or interested third parties), must be precluded from effective participation in an important pretrial matter merely because the defendant asserts that the factual or legal showing made in support of a particular motion should remain confidential.