Forget the xml part if you dont use it.

Insert the code like this in the skin ascx

<dnn:MENU runat="server" id="dnnMENU" rootmenuitembreadcrumbcssclass="MainMenu_BreadcrumbActive"/>

and the css

.MainMenu_BreadcrumbActive {
 
   
 background-color: #FF0000;
}

This will result in a red root menu when this root or the child to that root are active.

Just tested it in case I didnt remember. It works.

Jan