So I think I might of figured a solution (but you might know of a neater way to implement?)
mod_menu2panel > assets > query.mmenu.js
Line 270 change -
var $btn = $( '<a class="' + cls( 'subopen' ) + '" href="#' + id + '" />' ).insertBefore( $a );
if ( !$a.is( 'a' ) )
{
$btn.addClass( cls( 'fullsubopen' ) );
}
to
var $btn = $( '<a class="' + cls( 'subopen mmenu-fullsubopen' ) + '" href="#' + id + '" />' ).insertBefore( $a );
Basically I'm forcing the class to always include "menu-fullsubopen"
Is that an ok way to implement this?