The main reason why I provided Vertical Menu Layout, because not all End-Users are happy to use Horizontal Menu Layout. Sometimes, some pages are good to be displayed with Vertical Menu Layout.
You may simply switch from Horizontal Menu Layout to Vertical Menu Layout, by clicking on Theme Layout -> Vertical. Again and yes, it's so simple and easy like that!
As you can see, when you are browsing the Web Application in Vertical Menu Layout, then the Theme Selector contains the related settings to Vertical Menu Layout. You can adjust the settings that suits your needs from it.
Another good news is, some of settings in Theme Selector that can be implemented for Horizontal Menu Layout, will be used also for Vertical Menu Layout. In other words, they will share the same settings between one to each other.
In this demo site, when you are browsing via Phone mode for one of the submenu item under the Features menu item, some submenu items cannot be seen properly due to the screen height of the Phone. For such case, then you should switch to Horizontal Menu Layout from Theme Layout -> Horizontal.
The conclusion is, you can easily switch from Horizontal to Vertical (and vice versa) by using this template.