A bookmark hierarchy is an outline or stratified structure that places some bookmarks within others. In Foxit PDF Editor, multilevel bookmark hierarchy can be defined by properly dragging the bookmark icon in the Bookmark panel.
To nest a bookmark or move a bookmark out of nested position, please refer to Move a bookmark.
- To expand or collapse a bookmark
In a bookmark hierarchy, to expand a bookmark (a parent bookmark with child bookmarks) and show the child bookmarks, directly click the plus sign (+) next to the parent bookmark. Click the minus sign (-) to collapse the parent bookmark and hide its child bookmarks. To collapse all bookmarks, right-click any bookmark in the Bookmarks panel (or click the Options menu 
at the top of the Bookmarks panel) and choose Expand/ Collapse All Bookmarks. When no bookmarks are expanded in the Bookmarks panel, you can right-click any bookmark (or click the Options menu at the top of the Bookmarks panel) and choose Expand/ Collapse All Bookmarks to expand all bookmarks.