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add_action('print_media_templates', function(){
?>
<script type="text/html" id="tmpl-custom-gallery-setting">
    <h3 style="z-index: -1;">___________________________________________________________________________________________</h3>
    <h3>Custom Settings</h3>

    <label class="setting">
        <span><?php _e('Text'); ?></span>
        <input type="text" value="" data-setting="ds_text" style="float:left;">
    </label>

    <label class="setting">
        <span><?php _e('Textarea'); ?></span>
        <textarea value="" data-setting="ds_textarea" style="float:left;"></textarea>
    </label>

    <label class="setting">
        <span><?php _e('Number'); ?></span>
        <input type="number" value="" data-setting="ds_number" style="float:left;" min="1" max="9">
    </label>

    <label class="setting">
      <span><?php _e('Select'); ?></span>
      <select data-setting="ds_select">
        <option value="option1"> 'Option-1' </option>
        <option value="option2"> 'Option-2' </option>
      </select>
    </label>

    <label class="setting">
        <span><?php _e('Bool'); ?></span>
        <input type="checkbox" data-setting="ds_bool">
    </label>

</script>

<script>

    jQuery(document).ready(function()
    {
        _.extend(wp.media.gallery.defaults, {
        ds_text: 'no text',
        ds_textarea: 'no more text',
        ds_number: "3",
        ds_select: 'option1',
        ds_bool: false,
        ds_text1: 'dummdideldei'
        });

        wp.media.view.Settings.Gallery = wp.media.view.Settings.Gallery.extend({
        template: function(view){
          return wp.media.template('gallery-settings')(view)
               + wp.media.template('custom-gallery-setting')(view);
        }
        });

    });

</script>
<?php

});