Superfly Responsive Menu – WordPress Menu Plugin GPL Overview:
Superfly is a responsive WordPress menu plugin that generates space-efficient vertical push/sliding/static navigation, icon toolbar, or fullscreen menu of your choice. It can be used as standalone navigation or compliment your main menu. Superfly makes navigation much easier and user-friendly both on desktops and mobiles.
The concept of a slide-in vertical menu that proved itself on mobiles now shines on desktops too! It can be used as always visible navigation as well.
Superfly sits on a standard WordPress menu system. So you create a standard WP menu (or use existing) in WP admin on the Appearance/Menus page and then you choose this menu on Superfly’s options page as the source. Superfly injects a specified menu in its sidebar.
Also, you have the option to specify an alternative menu using a CSS selector if you want to use some existing menu on the page as a source for Superfly.
The plugin doesn’t replace existing theme menus. In this case, y you should disable the default menu in menu locations settings or hide it by simple CSS (ask to advise for this with your live URL).