app/views/filters/list/_input_options.html.erb
<% filter_values = filter.values || [] %>
<div class="advanced-filters--filter-value <%= value_visibility %> <%= filter_values.size > 1 ? 'multi-value' : '' %>"
data-filters-target="filterValueContainer"
data-filter-name="<%= filter.name %>">
<%= render partial: 'filters/list/select', locals: { filter: filter, selected_values: filter_values.first, multi_value: false } %>
<%= render partial: 'filters/list/select', locals: { filter: filter, selected_values: filter_values, multi_value: true } %>
</div>