1s-bitrix: why are the headers from the component template not installed?

Question

1C-Bitrix

In the template.php of the component template, I try to set and get the title in two ways:

print_r($arResult['PREVIEW_TEXT'].' '.$arResult['NAME']); echo '<br>';
$APPLICATION->SetTitle($arResult['PREVIEW_TEXT'].' '.$arResult['NAME']);
$APPLICATION->SetPageProperty("title", $arResult['PREVIEW_TEXT'].' '.$arResult['NAME']);
$APPLICATION->ShowTitle(); echo '<br>';
$APPLICATION->ShowTitle(false); echo '<br>';

I get:

KNX digital input module, 24 channels UCS-24.00
UCS-24.00
UCS-24.00

Headings in h1 and browser tab also do not change.

Answer 1

1. Setting headers from the cached part is useless - the template will not be executed on the next hit .
2. Someone below in the code exposes other headers. Probably the component itself.
You need to set headers after calling the component.

Answer 2

Read that these are deferred functions in Bitrix