SugarCRM sidecar retrieve fields' value that aren't visible in a view

record.php

<?php
$viewdefs['Leads']['base']['view']['record'] = array(
    'buttons' => array(
    .
    .
    .
    ),
    'panels' => array(
    .
    .
    .
    array(
        'name' => 'panel_hidden',
        'label' => 'LBL_RECORD_SHOWMORE',
        'hide' => true,
        'columns' => 2,
        'labels' => true,
        'labelsOnTop' => true,
        'placeholders' => true,
        'fields' => array(
            .
            .
            .
            array (
            	'name' => 'id_sheet',
            	'label'=> 'LBL_SMARTSHEET_SHEET',
            	'type' => 'sheetenum',
            	'readonly' => false,
            	'related_fields' => array(
            		'name_sheet',
            	),
            ),
            .
            .
            .
        ),
    ),
),