Hide/remove close button.

[WebGraf]

Do you know how we can hide or remove a close button for the ticket?

I have got all from PrimarySidebar but can't see what can help me.

add_hook('ClientAreaPrimaryNavbar', 1, function (MenuItem $primarySidebar)
{
$primarySidebar->getChild('Ticket Information');
var_dump($primarySidebar, true);
});

 

Anybody know how to fix this?

 

It was simple on the old themes:

$smarty->assign('showclosebutton', false);

 

But now....