Use this field the same way as the account Folder Exclusion option but it will apply to all folders

Double-Click Action

The Double-Click action for the list of Folders on Fling's main window can be assigned to one of the following:

• Open the Folder
  Select this option to view the contents of the local folder.
• Scan the Folder
  Select this option to scan for and upload changes to the local folder.
• Display Folder Properties
  Select this option to display the Properties for the item.