OneNote Gem Add-Ins

Question:

I just downloaded and installed OneNote, but after installing it, the Section List displayed at the top of the page is gone.
How do I restore to show the Section List tab at the top of the page?

Answer:

This is new version of the "Vertical Tab" layout.
Go to View tab -> Tabs Layout -> click the “Horizontal Tabs” menu item.
OneNote reverts back to show the Section List at the top of the page.