Auto Library Folder
From FDT Documentation
The Auto Library Folder is a folder that allows developers to easily consolidate their .SWC files. Whenever a .SWC is placed into this folder, it will automatically be added to your project's source path.
To create an Auto Library Folder, simple right click on a folder and select:
Classpath>Add as Auto Library Folder
The folder will turn green and be added to your source path.