The navigation pane in the left panel lacks many user friendly features. Presently, it is too restrictive on only showing down to H2. Authors should have the option to show any header within the navigation hierarchy for ease of organization and ease of navigation for the end user. It should function similarly to the navigation pane in Word when you use structured headers. Additionally, the end user should be able to expand/collapse the headers under each page (presently they are permanently expanded) and should be able to expand more than one section at a time (presently if you expand a new section, the previously expanded section collapses). All-in-all it's a very clunky user experience that should be improved to support more intuitive and more efficient navigation.