private function parseWidgetPageTree(PropertyInterface $property, array $propInfo)
    {
        if (isset($propInfo['sourceName'])
            || ('pageTree' !== $property->getWidgetType())
        ) {
            return;
        }

        // If the foreign key not set, then use an standard as fallback.
        if (!isset($propInfo['foreignKey'])) {
            $propInfo['foreignKey'] = 'tl_page.title';
        }

        $property
            ->setExtra(
                \array_merge(
                    [
                        'sourceName' => \explode('.', $propInfo['foreignKey'])[0],
                        'idProperty' => 'id'
                    ],
                    (array) $property->getExtra()
                )
            );
    }