DT FileCabinet is designed to use specific folders for documents printed from other DT Professional Suite applications. Copying such documents to other folders creates a reference to the original location; therefore, you cannot delete the original without also deleting any copied references.
This behavior does not apply to documents that are scanned or embedded in DT FileCabinet or that are printed to DT FileCabinet using the DT FileCabinet print driver. These documents can be copied, and then deleted from the original location.