Since the operations like copy/move/rename of some
types of files belonging to the project (e.g. java
source files) can have speacial meaning the
modules need to plug into this operation and
implement this extended meaning (e.g. change the
package declaration or rename the class). These
operations can be done accross the project
boundaries (e.g. the copy/move) and thus the code
implementing extended behavior of the operation
needs to access context of both the source project
and the target project.

Please, see the original request on dev@projects:
http://projects.netbeans.org/servlets/ReadMsg?msgId=413993&listName=dev