How Locks Affect Deletion

Locks prevent lists from being deleted.  This has two effects that users should be especially aware of:

1. (1)Children of locked lists cannot be deleted.
   

2. (2)Lists with locked children cannot be deleted.
   

The details are as follows...

Children of Locked Lists Cannot be Deleted

At first glance, this makes intuitive sense, but it is possible that the locked list is not the immediate parent and rather a list several levels up.  To the user, it may not be immediately apparent why deletion is disabled.  Consider the following diagram:

List A is locked, hence B, C, D and E are effectively locked despite not being explicitly locked themselves.  Attempts to delete D or E will fail despite their parent, C, not being explicitly locked.  This failure will not be immediately apparent unless one remembers that A is locked.

Lists with Locked Children cannot be Deleted

This makes less intuitive sense, but can be explained using the following diagram, where list C is locked:

When a delete operation is applied to list A, B will be deleted because it is not locked but C will remain because it is locked.  Objects D and E will remain because they are protected by C.  Since C cannot be orphaned, A cannot be deleted.  For A to be fully deleted, C must first be unlocked.

Note that it is possible that the locked list that is blocking the full deletion of a list may be deeply nested.