The navigation hierarchy works like a file browser (e.g. Windows Explorer). Folders may contain sub-folders. Selecting a node displays the view corresponding to the node. The types of folders used by the navigation list are described in an XML document that obeys the grammar of the xtk: navtree schema. The navigation hierarchy configuration is divided over several XML documents. It operates on a similar principle to schema extension: all documents are merged to generate a single document containing the whole configuration. To know more, click here.