This option toggles the nav bar being sticky or not for your left side navigation. Three column layout will always be sticky.
Left and Right Side Nav
In this section you can add links to different parts of your documentations as well as external links.
The default link for the logo will be your landing page, but you can also set it to your homepage URL from your project settings.
In this drop down you can select the first page that is shown when your users visit the site.
The section names such Documentation can be changed here and it will propagate throughout your entire instance.
Checking this will have the version number included in your breadcrumb links. Turn this off if you would like to hide the version number.
Hide Table of Contents
Checking this will hide the automatically-generated table of contents.