How do I override block class for Sales Order Products grid?

Question

I'm working on Magento 2.3.2 and am trying to override a block in adminhtml.

I overrode the template file perfectly fine, but it seems layout updates are being ignored?

This is the class that gets displayed with template hints with block class hints enabled:

Magento\GroupedProduct\Block\Adminhtml\Product\Composite\Fieldset\Grouped\Interceptor

The template path shows as my theme.

The theme's directory for overriding the template is:

app/design/adminhtml/Theme/Vendor/Magento_GroupedProduct

Which contains a folder for Block classes, a folder for templates and the last being for layout.

I copied the layout file from the module-grouped-product folder into my layout folder and made a change:

<block class="Vendor\Module\Block\FieldsetGrouped" 
       name="product.composite.fieldset.grouped" 
       before="product.composite.fieldset.options" 
       template="Magento_GroupedProduct::catalog/product/composite/fieldset/grouped.phtml" />

If I go to app/code/Vendor/Module/Block I can see the FieldsetGrouped class I made. However, after a full php bin/magento command list, still no changes.

I also copied the Block class into the Magento_GroupedProduct folder to see if it would work that way and it didn't seem to make a difference.

The area I'm specifically trying to update is the pop-up you get when clicking "configure" on grouped products when creating an order and adding products:

How do I tell Magento to listen to my xml update?

Thanks,

Answer 1

When working with theme you still have to use referenceBlock and referenceContainer tags to edit existing block or container.

This should resolve the problem:

<referenceBlock class="Vendor\Module\Block\FieldsetGrouped" 
   name="product.composite.fieldset.grouped" 
   before="product.composite.fieldset.options" 
   template="Magento_GroupedProduct::catalog/product/composite/fieldset/grouped.phtml" />

Don't forget to clear cache.

As a side note I think you are bit confused in what you are trying to do. If I am correct you are trying to replace class of a block in a theme. Why not change the class in module layout instructions? This will get messy pretty quickly.