If no menus are set to the vertical navigation menu, all pages are what will be rendered as navigation links thereby leaving a distorted layout. It is hence important you set up a menu to be rendered in place. In order to properly set up one, you will need to carry out the following:
i) Navigate to the Appearance Menu section within your WordPress dashboard
ii) Within the menu creation screen, fill in your menu name
iii) Click on the “Create Menu” button
iv) Select menu items from the left pane and click on the “Add to menu” button in each accordion based on your selection, in order to add the selected menu items
v) Click on the “Save Menu” button
vi) Scroll down the menu section to the “Menu Settings”
vii) Select the checkbox option “[Woffice] Main menu in the header.” and save your menu
Upon previewing the site, you will be in a position to have a proper view of the vertical navigation menu.