elementor-repeater-working.php

<?php

protected function _register_controls() {
  /**
   * Start a control section.
   */
  $this->start_controls_section(
      'section-ine-tabs',
      [ 'label' => __( 'INE Tabs', 'sage' ), ]
  );

  /**
   * Repeater Controls
   */
  $repeater = new Repeater();
  $repeater->start_controls_tabs( 'ine_tabs_repeater' );
  $repeater->start_controls_tab( 'tab', [ 'label' => __( 'Tab', 'sage' ) ] );
  $repeater->add_control(
      'title',
      [
          'label' => __( 'Tab Title', 'sage' ),
          'type'  => Controls_Manager::TEXT
      ]
  );
  $repeater->end_controls_tab();
  $repeater->end_controls_tabs();

  /**
   * Once the repeater controls are done
   * We need to ADD THE REPEATER as a Control
   */
  $this->add_control(
      'tabs',
      [
          'label'       => __( 'Tabs', 'sage' ),
          'type'        => Controls_Manager::REPEATER,
          'show_label'  => true,
          'default'     => [
              [
                  'title' => __( 'Default Tab', 'sage' ),

              ]
          ],
          'fields'      => array_values( $repeater->get_controls() ),
          'title_field' => '{{{title}}}',
      ]
  );
  $this->end_controls_section();
}

repeater.php

<?php
protected function _register_controls() {
    $this->start_controls_section(
        'section-ine-tabs',
        [ 'label' => __( 'INE Tabs', 'sage' ), ]
    );

    $repeater = new Repeater();
    $repeater->start_controls_tabs( 'ine_tabs_repeater' );
    $repeater->start_controls_tab( 'tab', [ 'label' => __( 'Tab', 'sage' ) ] );
    $repeater->add_control(
        'tab_title',
        [
            'label' => __( 'Tab Title', 'sage' ),
            'type'  => Controls_Manager::TEXT
        ]
    );
    $repeater->end_controls_tab();
    $repeater->end_controls_tabs();
    $this->end_controls_section();
}