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
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ii) Within the menu creation screen, fill in your menu name
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iii) Click on the “Create Menu” button
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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
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v) Click on the “Save Menu” button
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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
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Upon previewing the site, you will be in a position to have a proper view of the vertical navigation menu.