Multiple
The select can accept a list of selected options when it's
rendered with multiple flag. But this is an optional feature,
because it was not available in native CKAN's implementation.
{%- call ui.util.call(show_example) -%}
{%- raw %}
{%- set options = [{"value":"a"}, {"value":"b"}, {"value":"c"}, {"value":"d"}] -%}
{{ ui.select(label="List", multiple=true, options=options, selected=["b", "c"]) }}
{%- endraw %}
{%- endcall %}