The Tab menu switcher web part renders a menu not from cms content, but from user parameters.
Names of menu items are rendered from user specified web part property 'MenuItems' delimited by comma. Web part property 'ParameterName' is used as a URL parameter. Value of the parameter is counted from 0 to (count-1) of menu items.
The look of the web part is customizable with CSS. It uses class 'current'/'notcurrent' for the selected/unselected menu item.