I just merged 2 customers/vendors but one of those now shows inactive. Why?

When two or more customers/vendors are merged, you will be required to select a ‘Master customer/vendor’ from among the customers/vendors you’ve chosen to merge. This customer/vendor will be the one retained with the total transactions of all the merged customers/vendors, while the remaining will be marked inactive. The customers/vendors made inactive can be marked active again, but all previous transactions associated to them will be erased.