{% comment %}disabled_message is not part of the default render context but a tab can define it if needed.{% endcomment %}
{% if disabled_message %}
    <li role="presentation" class="disabled">
        <a href="#" title="{{ disabled_message }}">{{ label }}</a>
    </li>
{% else %}
    <li role="presentation"{% if request.GET.tab == tab_id or active_tab == tab_id %} class="active"{% endif %}>
        <a href="{{ url }}">{{ label }}</a>
    </li>
{% endif %}