What is a defendant's right to be personally present at trial?

For example, under the Sixth Amendment, a criminal defendant has the right to be personally present if his or her appearance is necessary to prevent interference with the defendant's opportunity for effective cross-examination. ( Kentucky v. Stincer (1987) 482 U.S. 730, 740, 744, fn. 17, 107 S.Ct. 2658, 96 L.Ed.2d 631; People v. Waidla (2000) 22 Cal.4th 690, 741, 94 Cal.Rptr.2d 396, 996 P.2d 46 ( Waidla ).) The right to be present arises under the Fourteenth Amendment if the defendant finds himself or herself at a stage ... that is critical to [the] outcome and the defendant's

[50 Cal.4th 682]