Tree structure persists between pages (Using session cookies).
The selected leaf is distinguished and persists between pages (Using session cookies).
"Expand All"; "Collapse All"; and "Expand to default" commands. (Optional)
Toggle Colour Level Guides. (Optional)
Synchronize the current page with the menu. (Optional)
Liquid. That is, the text can be resized and everything flows smoothly.
Accessible. Works if CSS turned off; Javascript off (tree set to "Expand All");
Cookies off (tree set to "Expand to default"; "Expand All"; or "Collapse All"
as developer desires); or all off.