always with my module, prestashop 1.6 I have a problem to correctly center and automatically my config page of my module in the admin, everything is displayed except that it is in the top left
public function __construct()
{
$this->bootstrap = true;
private function _displayForm()
{
$smarty->assign(array(
'url' => "http://".$_SERVER['HTTP_HOST'].__PS_BASE_URI__.'/',
$smarty->display(_PS_MODULE_DIR_ . 'monmodule/option.tpl');
option.tpl
<div id="modulecontent" class="bootstrap">
thanks in advance
</div>