There are two possible reasons:
1. If the intersection includes a DeptID that is planned for Inactivation, it will display as read-only to provide visibility but restrict additional planning.
2. If the intersection includes an Account that is managed by the Central Budget Office (such as 71110 - General Allocation, 71295 - Other Central Commitments,
5380X - Fee Remission - Plan) it will display as read-only.