Steps to reproduce the issue

<field name="images"
                       type="repeatable"
                       icon="images"
                       description="PLG_TINY_FIELD_TEMPLATE_FIELD_ELEMENTS_DESC"
                       label="Carousel images"
                       maximum="10"
                       filter="raw"
                       default="{'main_image':'','description':''}">
                    <fields name="params">
                        <fieldset hidden="true" name="images_modal" repeat="true">
                            <field name="main_image"
                                   type="media"
                                   preview="tooltip"
                                   directory="images"
                                   label="Main image"
                                   description="This is the main image for this slide" />
                            <field name="description"
                                   type="editor"
                                   editor="none"
                                   buttons="true"
                                   width="250"
                                   height="80"
                                   hide="image,module,readmore,pagebreak"
                                   label="Image description"
                                   description="The description text for the image" />
                        </fieldset>
                    </fields>
</field>

Expected result

Open a modal to choose an article

Actual result

A new page opens and the article cannot be selected

System information (as much as possible)

Joomla 3.5.1
Apache/2.4.12 (Ubuntu)
Database client version: libmysql - 5.6.28
PHP extension: mysqliDocumentation curlDocumentation mbstringDocumentation
PHP version: 5.6.11-1ubuntu3.1

Additional comments