Repeatable field not working with a modal_article-field.

Steps to reproduce the issue

1. add a repeatable with modal_article field:

      <!-- Fieldset: Dock -->
      <fieldset name="dock" label="Dock">

        <field name="dock_links" type="repeatable" icon="link" label="Links">
          <fieldset hidden="true" repeat="true" addfieldpath="/administrator/components/com_content/models/fields">
            <field name="name" type="text" label="Name" description="Social Name" filter="text"/>
            <field 
              name="article"
              type="modal_article"
              label="Select an article"
              select="true"
              edit="false"
              clear="true"
            />
          </fieldset>
        </field>

      </fieldset>
      <!-- ./Fieldset: Dock -->

Expected result

Show up two modals. Repeatable and Article selection.

Actual result

Nothing happens

System information (as much as possible)

OSX 10.13.5 (17F77)
Chrome 67.0.3396.79
Joomla 3.8.8

Additional comments