This is tree view:
Use Tree View if your information has sub-categories and you want to see a drop-down folder "explorer-style" view of it.
Adding a Table with Tree View
You can only add tree view at the moment you are creating table. To enable tree view, simply click the tree view checkbox at the bottom of the create table page.
Navigating to your Tree View
Look for the following icon in your table header:
Adding the tree view icon
Use the following url to add the tree view icon: src="/icons/crystal_project/32x32/actions/view_tree.png" alt="Tree View"/