<div class="accordion">
  {{#each category in content}}
    <div class="accordion-group">
      <div class="accordion-heading">
        <a {{bindAttr href="category.collapsibleHref"}} class="accordion-toggle" data-toggle="collapse" data-parent="metadata-accordion">
          {{category.name}}
        </a>
      </div>
      <div {{bindAttr id="category.collapsibleId"}} class="accordion-body collapse">
        <div class="accordion-inner">
          <select multiple="multiple" style="width:180px">
            {{#each value in category.metadataValues}}
              <option {{bindAttr value="value.id"}}>{{value.text}}</option>
            {{/each}}
          </select>
        </div>
      </div>
    </div>
  {{/each}}
</div>

<div class="accordion">
  {{#each category in content}}
    <div class="accordion-group">
      <div class="accordion-heading">
        <a {{bindAttr href="category.collapsibleHref"}} class="accordion-toggle" data-toggle="collapse" data-parent="metadata-accordion">
          {{category.name}}
        </a>
      </div>
      <div {{bindAttr id="category.collapsibleId"}} class="accordion-body collapse">
        <div class="accordion-inner">
          {{view Em.Select
            contentBinding="category.metadataValues"
            optionValuePath="content.id"
            optionLabelPath="content.text"
            multiple="true"
          }}
        </div>
      </div>
    </div>
  {{/each}}
</div>

Use Ember.Select for listing of metadata
Use Ember.Select for listing of metadata
