De Ayala v. Mackie
In De Ayala v. Mackie, 193 S.W.3d 575 (Tex. 2006), the supreme court held that the trial court's order denying a plea to the jurisdiction and refusal to remove an executor was not appealable.
The supreme court explained that "an order denying a motion to dismiss an entire proceeding for want of subject-matter jurisdiction is more like a prelude than a finale." Id.
"It certainly does not dispose of a claim that, if asserted independently, would be the proper subject of a lawsuit." Id.
It noted further that under Crowson v. Wakeham, 897 S.W.2d 779 (Tex. 1995), "the trial court's order was interlocutory because it did not dispose of all parties or issues in a particular phase of the proceedings." De Ayala, 193 S.W.3d at 579.
According to the supreme court, "because an order denying a plea to the jurisdiction and refusing to remove an executor does not end a phase of the proceedings, but sets the stage for the resolution of all proceedings, the order is interlocutory." Id.