Behavior of add-on .post.tpl and override.tpl

hello!!
I have created an add-on that changes the value of the title $title that is displayed when adding a product.
override.tpl could not change the value of $title, post.tpl could change the value of $title.
why???
Does anyone know why the behavior is known?
Also, do you know how I can change the $title value in override.tpl as well?

cs-cart

Multi-Vendorv4.15.2_JP_1

Target file

/design/backend/templates/views/products/update.tpl

{hook name="products:update_mainbox_params"}

{if $id}
    {$title = $product_data.product|strip_tags}
{else}
    {$title = __("new_product")}
{/if}

{/hook}

{include file="common/mainbox.tpl"
    title=$title
    content=$smarty.capture.mainbox
    select_languages=(bool) $id
    buttons=$smarty.capture.buttons
    adv_buttons=$smarty.capture.adv_buttons
}

Addon file

/design/backend/templates/addons/products_settings_change/hooks/products/update_mainbox_params.override.tpl

{if $id}
    {$title = $product_data.product|strip_tags}
{else}
    {if $addons.products_settings_change.add_product_title_text}
        {$title = $addons.products_settings_change.add_product_title_text}
    {else}
        {$title = __("new_product")}
    {/if}
{/if}
{$title = $title scope="parent"}

Please try scope=root

Thanks for the reply.
I tried scope=root but unfortunately it didn’t work.

It is required to examine issue on your server. It can be related with another module

Hi!

Instead of trying to assign variable to itself:

{$title = $title scope="parent"}

Try to add the scope directly to a statement where you define the new value of the $title variable. Like:

{$title = $product_data.product|strip_tags scope=parent}

instead of

{$title = $product_data.product|strip_tags}

Also (since you are only changing the variable’s value), please try to change the file name from override to post ( update_mainbox_params.post.tpl).