function wpf_render_crm_field_select( $setting, $meta_name, $field_id, $field_sub_id = null ) {

    echo '<select id="' . $field_id . (isset($field_sub_id) ? '-' . $field_sub_id : '') . '" class="select4-crm-field" name="' . $meta_name . '[' . $field_id . ']' . (isset($field_sub_id) ? '[' . $field_sub_id . ']' : '') . '[crm_field]" data-placeholder="Select a field">';

        echo '<option></option>';

        $crm_fields = wp_fusion()->settings->get('crm_fields');

        if(!empty( $crm_fields )) {

            foreach( $crm_fields as $group_header => $fields ) {

                // For CRMs with separate custom and built in fields
                if(is_array($fields)) {

                    echo '<optgroup label="' . $group_header . '">';

                        foreach($crm_fields[$group_header] as $field => $label) {

                            if(is_array($label))
                                $label = $label['label'];

                            echo '<option ' . selected(esc_attr( $setting ), $field ) . ' value="' . $field . '">' . $label . '</option>';
                        }


                    echo '</optgroup>';

                } else {

                    $field = $group_header;
                    $label = $field;

                    echo '<option ' . selected(esc_attr( $setting ), $field ) . ' value="' . $field . '">' . $label . '</option>';


                }

            }

        }

    echo '</select>';

}