Modifying Attributes of Nested References
Modifications to attributes of nested attachments depend on the path to the attachment through the parent file.
For example, assume that c.dgn is a nested attachment in a.dgn and c.dgn is attached once through b.dgn, once through d.dgn and once through e.dgn.
Using the example above, if the ByLevelColor of c.dgn was changed through b.dgn, d.dgn and e.dgn each nested attachment would reflect each individual change through a.dgn and not be uniform with respect to the appearance of c.dgn through b.dgn, as shown in the figure below.
However, if b.dgn was attached twice, the change to c.dgn through b.dgn would propagate to both instances. This is regardless of whether the parent attachment containing the nested attachment is itself nested into another file. That is, the uniformity is based upon path to the nested attachment through the parent, not the file to which the parent is attached.