EDIT

/**

 * Composes the view on specimens and occurrences as derivate tree

 * starting from the field unit including all derivatives.

 *

 * @param array $root_unit_dtos

 *   list of SpecimenOrObservationDTOs

 *

 * @return array

 *   The Drupal render array

 *

 * @ingroup compose

 * @see CDM_SPECIMEN_LIST_VIEW_MODE_OPTION_DERIVATE_TREE

 *

 */

function compose_specimen_table_top_down_new(array $root_unit_dtos, $with_details = true, $focused_unit_uuid = null) {

  $derivation_tree = derived_units_tree($root_unit_dtos, $with_details);

  $render_array = [];

  $render_array['derived-unit-tree'] = $derivation_tree;

  _add_js_derivation_tree('.derived-unit-tree');

  if(is_uuid($focused_unit_uuid)){

    _add_js_derivation_tree_focus_unit($focused_unit_uuid);

  }

  return $render_array;

}

/**

 * Creates the root levels and trees for all subordinate derivatives.

 *

 * See derived_units_sub_tree()

 *

 * @param array $root_unit_dtos

 *     list of SpecimenOrObservationDTOs

 *

 * @return array

 *    An array which can be used in render arrays to be passed to the

 * theme_table() and theme_list().

 */

function derived_units_tree(array $root_unit_dtos, $with_details = true) {

  RenderHints::pushToRenderStack('derived-unit-tree');

  RenderHints::setFootnoteListKey('derived-unit-tree');

  $root_items = [];

  //we need one more item to contain the items of one level (fieldunit, derivate data etc.)

  foreach ($root_unit_dtos as &$sob_dto) {

    $content_wrapper_markup = '';

    if($with_details){

      $field_unit_dto_render_array = compose_cdm_specimen_or_observation_dto_details_grid($sob_dto);

      $content_wrapper_markup = '<div class="unit-content-wrapper">' // allows to apply the borders between .derived-unit-tree-root and .unit-content

        . '<div class="unit-content">' . drupal_render($field_unit_dto_render_array) . '</div>'

        . '</div>';

    }

    $root_item = [

      '#prefix' => '<div class="derived-unit-tree">',

      '#suffix' => '</div>',

      '#type' => 'container',

      '#attributes' => [

        'class' => [

          'derived-unit-item derived-unit-tree-root',

          html_class_attribute_ref($sob_dto),

        ],

      ],

      'div-container' => [

        'root-item-and-sub-tree' => [

          markup_to_render_array(derived_units_tree_node_header($sob_dto)

            . $content_wrapper_markup),

        ],

      ],

    ];

    if (isset($sob_dto->derivatives) && sizeof($sob_dto->derivatives) > 0) {

      usort($sob_dto->derivatives, 'compare_specimen_or_observation_dtos');

      // children are displayed in a nested list.

      $root_item['div-container']['root-item-and-sub-tree'][] = derived_units_sub_tree($sob_dto->derivatives, $with_details);

    }

    $root_items[] = $root_item;

  }

  $root_items['footnotes'] = markup_to_render_array(render_footnotes());

  RenderHints::popFromRenderStack();

  return $root_items;

}

/**

 * @param array $unit_dtos

 *

 * @return array

 */

function derived_units_sub_tree(array $unit_dtos, $with_details = true) {

  $list_items = derived_units_as_list_items($unit_dtos, $with_details);

  $derivation_tree = [

    '#theme' => 'item_list',

    '#type' => 'ul',

    '#attributes' => [

      // NOTE: class attribute "derived-unit-item" is important for consistency with subordinate <ul> elements produced by the drupal theme function

      'class' => CDM_SPECIMEN_LIST_VIEW_MODE_OPTION_DERIVATE_TREE . ' derived-unit-item derived-unit-sub-tree',

    ],

    '#items' => $list_items,

  ];

  return $derivation_tree;

}

/**

 * Creates render array items for FieldUnitDTO or DerivedUnitDTO.

 *

 * @param array $root_unit_dtos

 *     list of SpecimenOrObservationDTOs

 *

 * @return array

 *    An array which can be used in render arrays to be passed to the

 * theme_table() and theme_list().

 */

function derived_units_as_list_items(array $root_unit_dtos, $with_details = true) {

  $list_items = [];

  //we need one more item to contain the items of one level (fieldunit, derivate data etc.)

  foreach ($root_unit_dtos as &$sob_dto) {

    $item = [];

    $item['class'] = ['derived-unit-item ', html_class_attribute_ref($sob_dto)];

    // data" element of the array is used as the contents of the list item

    $item['data'] = [];

    $unit_content_markup = '';

    if($with_details){

      $units_render_array = compose_cdm_specimen_or_observation_dto_details_grid($sob_dto);

      $unit_content_markup = '<div class="unit-content derived-unit-details-grid">' . drupal_render($units_render_array) . '</div>';

    }

    $item['data'] = derived_units_tree_node_header($sob_dto)

      . $unit_content_markup;

    if (isset($sob_dto->derivatives) && sizeof($sob_dto->derivatives) > 0) {

      usort($sob_dto->derivatives, 'compare_specimen_or_observation_dtos');

      // children are displayed in a nested list.

      $item['children'] = derived_units_as_list_items($sob_dto->derivatives, $with_details);

    }

    $list_items[] = $item;

  }

  return $list_items;

}

/**

 * @param $sob_dto

 *

 * @return string

 */

function derived_units_tree_node_header($sob_dto) {

  $link =  cdm_internal_link(path_to_specimen($sob_dto->uuid), null);

  return '<div class="unit-header"><div class="unit-label">' . $sob_dto->label . '<span class="page-link">' . $link . '</span></div></div>';

}

    $render_array['derivation_tree'] = compose_specimen_table_top_down_new($derivation_tree_roots, false, $sob_dto->uuid);