Advanced users can define sub-projects. For example, if you define the following project and sub-project as:
Project name: PROJECT1
Work folder:C:\Project1
Include sub-folders: Yes
and
Project name: PROJECT1 Documents
Work folder:C:\Project1\Doc
Operations on PROJECT1 will then affect all files within the C:\PROJECT1 tree, including the PROJECT1 Documents project. Operations on PROJECT1 Documents will affect files within the Doc sub-folder only.