Typo3 v10 - Content Elements in Extension Empty - typo3

Question

I have a typo3 extension which allows to create Content Elements within the extension - in typo3 v9 it works fine but on typo3 v10 it doesn’t, when I debug in the template i got this result:
contentElements => protected TYPO3\CMS\Extbase\Persistence\Generic\LazyObjectStorageprototypeobject (empty)
The Content Element is created and in the backend also correctly visible within the Dataset
I also tried to have a look at tx_news which implements a simular behaiver but I doesn’t have a clue, for me it seems that I done right but yeah … , following some code snippets I used, may you have an Idea:
In the setup.typoscript:
lib.contenttabs_fecontenttabs.contentElementRendering = RECORDS
lib.contenttabs_fecontenttabs.contentElementRendering {
tables = tt_content
source.current = 1
dontCheckPid = 1
}
In the Model (I tried to use the sam as news):
/**
* Get content elements
*
* #return \TYPO3\CMS\Extbase\Persistence\ObjectStorage
*/
public function getContentElements()
{
return $this->contentElements;
}
/**
* Set content element list
*
* #param \TYPO3\CMS\Extbase\Persistence\ObjectStorage $contentElements content elements
*/
public function setContentElements($contentElements)
{
$this->contentElements = $contentElements;
}
/**
* Adds a content element to the record
*
* #param \Moc\Contenttabs\Domain\Model\TtContent $contentElement
*/
public function addContentElement(\Moc\Contenttabs\Domain\Model\TtContent $contentElement)
{
if ($this->getContentElements() === null) {
$this->contentElements = new \TYPO3\CMS\Extbase\Persistence\ObjectStorage();
}
$this->contentElements->attach($contentElement);
}
/**
* Get id list of content elements
*
* #return string
*/
public function getContentElementIdList()
{
return $this->getIdOfContentElements();
}
/**
* Get translated id list of content elements
*
* #return string
*/
public function getTranslatedContentElementIdList()
{
return $this->getIdOfContentElements(false);
}
/**
* Collect id list
*
* #param bool $original
* #return string
*/
protected function getIdOfContentElements($original = true)
{
$idList = [];
$contentElements = $this->getContentElements();
if ($contentElements) {
foreach ($this->getContentElements() as $contentElement) {
if ($contentElement->getColPos() >= 0) {
$idList[] = $original ? $contentElement->getUid() : $contentElement->_getProperty('_localizedUid');
}
}
}
return implode(',', $idList);
}
In the Template:
<f:cObject typoscriptObjectPath="lib.contenttabs_fecontenttabs.contentElementRendering">
{tab.contentElementIdList}
</f:cObject>
Some of the TCA Code (which seems to works fine):
'content_elements' => [
'exclude' => 1,
'l10n_mode' => 'mergeIfNotBlank',
'label' => 'Content Elements',
'config' => [
'type' => 'inline',
'allowed' => 'tt_content',
'foreign_table' => 'tt_content',
'foreign_sortby' => 'sorting',
'foreign_field' => 'tx_tabs_content_elements',
'minitems' => 0,
'maxitems' => 99,
'overrideChildTca' => [
'columns' => [
'colPos' => [
'config' => [
'default' => 99
]
],
'CType' => [
'config' => [
'default' => 'textmedia'
]
]
]
],
'appearance' => [
'collapseAll' => 1,
'expandSingle' => 1,
'levelLinksPosition' => 'bottom',
'useSortable' => 1,
'showPossibleLocalizationRecords' => 1,
'showRemovedLocalizationRecords' => 1,
'showAllLocalizationLink' => 1,
'showSynchronizationLink' => 1,
'enabledControls' => [
'info' => false,
]
]
]
],
Thanks in advance!