How to prevent Project Task "State" field from locking when creating a child task

[Alex Wong]

Which business rule is responsible for locking (greying out) the "State" field of a parent task when a child task is created? I recently disabled the business rule "Process State Change" on the pm_project_task table to prevent parent tasks from auto-closing when all child tasks have been completed. However, because the parent task's "State" field is locked, I can't change this to closed at a later date.

[MBarrott]

@Namita Mishra - I tried creating a milestone project task which was a child to the parent task. I created a checklist, checked them all off and closed out the record. The parent task is still sitting as "pending" so I'm not sure how this BR works or what influences the state field to change. 

Parent: 

Child Task (milestone checked in details tab):