(a) In a county in which there is no statutory probate court or county court at law exercising original probate jurisdiction, the county court has original jurisdiction of guardianship proceedings.
(b) In a county in which there is no statutory probate court, but in which there is a county court at law exercising original probate jurisdiction, the county court at law exercising original probate jurisdiction and the county court have concurrent original jurisdiction of guardianship proceedings, unless otherwise provided by law. The judge of a county court may hear guardianship proceedings while sitting for the judge of any other county court.
(c) In a county in which there is a statutory probate court, the statutory probate court has original jurisdiction of guardianship proceedings.
(d) From the filing of the application for the appointment of a guardian of the estate or person, or both, until the guardianship is settled and closed under this chapter, the administration of the estate of a minor or other incapacitated person is one proceeding for purposes of jurisdiction and is a proceeding in rem.