California Code, Probate Code - PROB § 2205

(a) Except as provided in Section 304 of the Welfare and Institutions Code, and subject to the provisions specified in subdivision (b), upon the filing of an order appointing a guardian of the person of a minor in a guardianship proceeding, including an order appointing a temporary guardian of the person of the minor, the court in the guardianship proceeding shall have exclusive jurisdiction to determine all issues of custody or visitation of the minor until the guardianship proceeding is terminated.

(b) This section is subject to the provisions of Sections 1510 of this code, and 8714, 8714.5, and 8802 of the Family Code, relating to consolidation of guardianship and adoption proceedings and the court where the consolidated case is to be heard and decided.