Tree View
Tree View is enabled by default and is located just below the Quick Launch Bar. It provides links to other areas of the site, such as Subsites (if present), Libraries, Lists, etc. Each of the items that contain other objects can be expanded much like Windows Explorer. You can navigate down the tree view. For example, you can click on a library name and open the contents within Tree View to access links to the folders and documents within that library. Tree View is not configurable. To disable Tree View navigate to Look and Feel section in Site Settings and click on Tree View.