index.php

[iskono]

add <ul class="nav navbar-nav">
in row:
$_DATA['menu'] = '<ul>';
change it to
$_DATA['menu'] = '<ul class="nav navbar-nav">';

so it can work with most of templates by adding

before ul
template example
example : <ul id="nav" class="nav">
<nav>{{ $_CMS['menu'] }}</nav> </ul>

[Jorge Moreno]

updated code in the recent commit 2b0ae1d should resolve that.