Shopware admin extend property details page with one to many relation

Question

Trying to extend property with one to many relation to be able to categorize each property group. I did the extension and the migrations. all Seems to be working fine except from saving the relation in the admin panel property details page "/sw/property/detail/{id}" where I added a dropdown field using the sw-entity-single-select. Any help is appreciated. Here is my currently code:

class PropertyGroupExtension extends EntityExtension
{
    public function getDefinitionClass(): string
    {
        return PropertyGroupDefinition::class;
    }

    public function extendFields(FieldCollection $collection): void
    {
        $collection->add(
            (new FkField(
                'property_group_category_id',
                'propertyGroupCategoryId',
                PropertyGroupCategoryDefinition::class
            ))->addFlags(new ApiAware())
        );

        $collection->add(
            (new ManyToOneAssociationField(
                'propertyGroupCategory',
                'property_group_category_id',
                PropertyGroupCategoryDefinition::class,
                'id',
                false
            ))->addFlags(new ApiAware())
        );
    }
}
class PropertyGroupCategoryDefinition extends EntityDefinition
{
    public const ENTITY_NAME = 'property_group_category';

    public function getEntityName(): string
    {
        return self::ENTITY_NAME;
    }

    public function getEntityClass(): string
    {
        return PropertyGroupCategoryEntity::class;
    }

    protected function defineFields(): FieldCollection
    {
        return new FieldCollection([
            (new IdField('id', 'id'))->addFlags(new ApiAware(), new PrimaryKey(), new Required()),
            (new StringField('name', 'name'))->addFlags(new ApiAware(), new Required()),
            (new OneToManyAssociationField('propertyGroups', PropertyGroupDefinition::class, 'property_group_category_id'))->addFlags(new ApiAware()),
        ]);
    }
}
class PropertyGroupCategoryEntity extends Entity
{
    use EntityIdTrait;

    /**
     * @var string
     */
    protected $name;

    /**
     * @var PropertyGroupCollection|null
     */
    protected $propertyGroups;

    public function getName(): string
    {
        return $this->name;
    }

    public function setName(string $name): void
    {
        $this->name = $name;
    }

    public function getPropertyGroups(): ?PropertyGroupCollection
    {
        return $this->propertyGroups;
    }

    public function setPropertyGroups(PropertyGroupCollection $propertyGroups): void
    {
        $this->propertyGroups = $propertyGroups;
    }
}
#[Package('core')]
class Migration1726207525CreatePropertyGroupCategory extends MigrationStep
{
    public function getCreationTimestamp(): int
    {
        return 1726207525;
    }

    public function update(Connection $connection): void
    {
        $connection->executeStatement('
            CREATE TABLE `property_group_category` (
                `id` BINARY(16) NOT NULL,
                `name` VARCHAR(255) NOT NULL,
                `created_at` DATETIME(3) NOT NULL,
                `updated_at` DATETIME(3) NULL,
                PRIMARY KEY (`id`)
            ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
        ');

        $connection->executeStatement('
            ALTER TABLE `property_group`
            ADD COLUMN `property_group_category_id` BINARY(16) NULL AFTER `filterable`,
            ADD CONSTRAINT `fk.property_group.property_group_category_id` FOREIGN KEY (`property_group_category_id`)
                REFERENCES `property_group_category` (`id`) ON DELETE SET NULL ON UPDATE CASCADE;
        ');
    }

}

and here is where i need the help. this is the admin shopware component already overridden by my plugin.

import template from './sw-property-group-detail.html.twig';
import {Component} from 'Shopware';

Component.override('sw-property-detail-base', {
    template,

    inject: ['repositoryFactory'],


    computed: {
        propertyGroupRepository() {
            return this.repositoryFactory.create('property_group');
        },

        propertyGroupCategoryRepository() {
            return this.repositoryFactory.create('property_group_category');
        },
    },

    methods: {
        onChange(id) {
            this.propertyGroup.propertyGroupCategoryId = id;
            if (id) {
                this.propertyGroupCategoryRepository.get(id).then((category) => {
                    this.propertyGroup.propertyGroupCategory = category;
                });
            } else {
                this.propertyGroup.propertyGroupCategory = null;
            }

            console.log(this.propertyGroup) // the data is here but is not saved on click the save button. is there anything here i am missing out?
        },
    }
});

template

{% block sw_property_detail_base_visible_on_detail %}
    {% parent %}
    <sw-entity-single-select
            id="propertyGroupCategory"
            ref="propertyGroupCategory"
            entity="property_group_category"
            :criteria="propertyGroupCategoryCriteria"
            :value="propertyGroup.propertyGroupCategoryId"
            label="Group By"
            placeholder="Group By"
            @update:value="onChange"
    ></sw-entity-single-select>
{% endblock %}
sw/property/detail/

services:

        <service id="MyProject\Core\Content\Property\PropertyGroupExtension">
            <tag name="shopware.entity_extension" />
        </service>

        <service id="MyProject\Core\Content\PropertyGroupCategory\PropertyGroupCategoryDefinition">
            <tag name="shopware.entity.definition" entity="property_group_category" />
        </service>

Answer 1

The reason was not working its because of the way was registered in the service definition. specifically was a typo in the tag name.

Instead of

        <service id="MyProject\Core\Content\Property\PropertyGroupExtension">
            <tag name="shopware.entity_extension" />
        </service>

should be

        <service id="MyProject\Core\Content\Property\PropertyGroupExtension">
            <tag name="shopware.entity.extension" />
        </service>

The correct tag name for the EntityExtension is shopware.entity.extension