Texas Estates Code - EST § 33.052. Concurrent Venue

(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.