Mississippi Code Title 91. Trusts and Estates § 91-7-19

Any proponent of a will for probate may, in the first instance, make all interested persons parties to his application to probate the will, and in such case all who are made parties shall be concluded by the probate of the will. At the request of either party to such proceeding, an issue shall be made up and tried by a jury as to whether or not the writing propounded be the will of the alleged testator.