Working with Markups > Annotation Sets and Folders > About Annotation Folders
  
About Annotation Folders
Annotation folders are shown in the tree view of the Annotation Sets navigator. When you select a folder, thumbnail previews of the annotation sets in the folder are displayed in the lower half of the Annotation Sets Tree. You must be in Tree View to work with annotation folders. You can perform the following operations on Annotation Folders:
Create new folders and name them according to their context.
Edit folder name and content.
Organize and reorder folders by dragging and dropping them in the tree view.
Nest folders.
Load the annotation set in the viewer.
You cannot keep an empty folder in the Annotation Sets Tree. When you remove all the annotation sets from a folder, the folder is automatically deleted.