Magento Certified Developer GuideCategory: 3.2 BlocksHow are a block’s children rendered? Once you added a child to the block, can you expect it will be rendered automatically?
Manish Prakash Staff asked 5 years ago

Most magento blocks dont render child blocks automatically. Only few blocks like ‘core/text_list’, ‘page/html_wrapper’, ‘core/flush’ do this. In other blocks we need to manually call them using “$this->getChildHtml()” function in the template files.