(a) If applications for probate proceedings involving the same estate are filed in two or more courts having concurrent venue, the court in which a proceeding involving the estate was first commenced has and retains jurisdiction of the proceeding to the exclusion of the other court or courts in which a proceeding involving the same estate was commenced.
(b) The first commenced probate proceeding extends to all of the decedent's property, including the decedent's estate property.
Official text of the Texas Estates Code as published by the Texas Legislative Council.