You can try with this ("Multiplier module"). I used different approach to get same result like with Joomla repeatable form field type, and also with that avoid "pop-ups inside popup". Still in development phase, but maybe you can try with that concept. Regards.
What I did to solve similar problem?
I had a similar problem with default Joomla repeatable form field type, especially with "pop-up" form fields type (eg. Joomla "date"). Because of that I created some kind of module pattern (mod_multiplier) where I used different approach -> I wouldn't repeat form of fields (section), I want to use same section for multiple insertion.
Module mod_multiplier
Inside module xml file are 3 reserved fields "wrapper", "repeater", and "content".
Inside "wrapper" is the place for "repeatable" fields:
<fieldset name="basic" addfieldpath="/modules/mod_multiplier/models/fields">
<!-- Wrapper is container for repeatable fields-->
<fields name="wrapper">
<!--This is the place where you insert your fields-->
</fields>
<field name="repeater" label="" type="repeater" />
<field name="content" hidden="true" label="Content" type="hidden" />
</fieldset>
All content would be stored inside "content" field in JSON format. Every time when we press form "Add" button we will add one row of data to "content" field. After all, inside "content" we will have rows of data.
How that look inside tmpl/default.php file and how to get fields values?
Hierarchical data structure has 3 levels: rows, row and field.
- all data => $rows
- one row of data => $row
- one field => $row->field_name
Practical example from mod_multiplier:
Inside "wrapper" are fields "country", and "city" and we call them by name (inside tmpl/default.php) like this:
<ul>
<?php foreach ($rows as $row):?>
<li>
<?php echo $row->country;?>:<?php echo $row->city;?>
</li>
<?php endforeach; ?>
</ul>