Description -
Why is this feature important to you - We never want user to have the ability to delete project update comments however, there are times when a user needs to remove their document/proof comments. Need the granular functionality to keep project update comments, while allowing users the ability to delete document/proof comments.
How would you like the feature to work - See above
Current Behaviour - Unchecking the "Never allow users to delete comments" setting will indeed grant users the ability to delete both proof/document comments and project update comments.
Unfortunately, the current settings don't offer a granular control for that distinction. The "Never allow users to delete comments" option applies universally to all comment types, including project updates.