firefly-iii/resources/views/form/multi-select.twig

<div class="{{ classes }}" id="{{ name }}_holder">
    <label for="{{ options.id }}" class="col-sm-4 control-label">{{ label }}</label>

    <div class="col-sm-8">
        {{ Html.multiselect(name~"[]", list, selected).id(options.id).attribute('size',12).class('form-control').attribute('autocomplete','off').attribute('spellcheck','false').attribute('placeholder', options.placeholder) }}
        {% include 'form.help' %}
        {% include 'form.feedback' %}

    </div>
</div>